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2^0 Electro-Platers 
Hand-Book 



By 

JAMES H. WESTON 



ILL USTRA TED B Y 
L. ELLIOTT BROOKES 




FREDERICK J. DRAKE & CO. 

211-213 E. Madison Street CHICAGO 

1905 



LIBRARY of CONGRESS 


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COPYRIGHT, 1905 

BY 

FREDERICK J. DRAKE & CO. 

CHICAGO 






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This book has been written to meet the require- 
ments of platers desiring a practical and yet 
non-technical work on electro-plating. The sub- 
ject-matter given herein has been obtained from 
platers of practical experience, and the construe 
ticn and operation of the different devices used in 
the electro-deposition of metals are fully described 
and illustrated. 

It contains useful information for platers and 
others who wish to become acquainted with the 
practical art of the electro-deposition of metals 
and their alloys, including Electro-deposition of 
Metals, Electro-deposition of Alloys, Electro-plat- 
ing Dynamos, Electro-plating Solutions and Elec- 
tro-plating Apparatus. 

The Author 



The Electro-platers Hand-book 



ELECTRICAL RULES AND FORMULAS 

In order to enable the operator of an electro- 
plating plant to intelligently handle the batteries 
or dynamo and plating vats and turn out work 
properly, it is almost absolutely necessary that 
some knowledge of the fundamental principles 
of electricity should be had. 

Electricity or electrical energy may be gener- 
ated in several ways — mechanically, chemically 
and statically. By whatever means it is pro- 
duced, there are many properties which are com- 
mon to all. There are also distinctive properties. 
The current supplied by a battery is of the direct 
form and will flow continuously until the battery 
is practically exhausted. 

The dynamo current is primarily of an alter- 
nating nature or one which reverses its direction 
of flow rapidly. In use, this alternating current 
is changed into a direct or continuous current 
flowing in one direction only, by means of a 
commutator. 

The cause of a manifestation of energy is 
force, if of electromotive energy, that is to say of 
electric energy in the current form, it is called 

7 



8 THE ELECTRO-PLATERS HAND-BOOK 

electromotive force. What this condition of 
excitation may be is a profound mystery, like 
gravitation and much else in the physical world. 
The practical unit of electromotive force is the 
volt. 

When electromotive force does work a current 
is produced. The practical unit of current is 
the ampere. 

A current of electricity passes through some 
substances more easily than through others. A 
current of one ampere is maintained by one volt 
through a resistance of one practical unit. This 
unit is called the ohm. 

The volt, the unit of electromotive force, will 
generate a current of one ampere in a circuit hav- 
ing a resistance of one ohm. There are several 
specified equivalents for estimating the exact 
value of one volt, but these usually refer to the 
determined capacity of some given type of dry cell. 

The ampere, the unit of current strength, has 
been fixed as the equivalent of a current strength 
which can deposit .00033 grams of metallic cop- 
per, by the electro -plating process, in each 
second of time. In this respect it measures not 
only the current intensity, or available working 
energy, but also the rapidity of its work. The work 
above stated might readily be accomplished by a 
given current in ten seconds, instead of in one, 
but such a current would not have the value of 
one ampere, only of 1-10 ampere — since it would 
require ten times as long to accomplish the same 
result. 



ELECTRICAL RULES AND FORMULAS 9 

An analogy for the ampere is the miner's inch, 
which represents the product of an orifice one 
inch square, through which water is allowed to 
escape from a tank, by the height of the column 
of water in the tank, in inches. The miner's 
inch is, therefore, in the first place, a measure 
of rate or velocity, giving inch-seconds, or the 
number of cubic inches of water passed in each 
second of time. Thus, while water flows at the 
rate of so many miner's inches, the electrical 
current flows at the rate of so many amperes, the 
rate per second, in both cases, being directly 
relative to the original pressure at the source. 
It is inaccurate to speak of an ampere per second, 
since such an expression means simply a current 
of one ampere. In speaking of a current of ten 
amperes, it does not refer to the amount of cur- 
rent passed in ten seconds, but to that passing in 
one second. 

The ohm, the unit of resistance, measures not 
only the relative resistance of a circuit composed 
of a conducting wire of a given length and diam- 
eter, as compared with wires of different length 
and diameter, composed of the same material, but 
also the specific resistance, which refers to the 
variations in resistance found between wires of 
the same length and cross-section, but of different 
materials. The different resistance of different 
metals, as found in circuits, precisely similar in all 
other dimensions, is demonstrated in the fact that, 
while a silver wire shows a conductivity of 100, and 
one of copper, 99, a wire of iron gives only 16.80. 



10 THE ELECTRO-PLATERS HAND-BOOK 

Ohm's Law. This law expresses the relation in 
an active electric circuit of current, electromo- 
tive force or voltage and resistance. These three 
factors are always present in such a circuit. Its 
general statement is as follows: 

In an active electric circuit the current is equal 
to the electromotive force divided by the resist- 
ance. 

This law can be expressed in various ways as it 
is transposed. It may be given as a group of 
rules, to be referred to under the general title 
given above. 

1. The current is equal to the electromotive 
force divided by the resistance. 

c E 

2. The electromotive force is equal to the cur- 
rent multiplied by the resistance. 

E-CxR 

3. The resistance is equal to the electromotive 
force divided by the current. 

4. The current varies directly with the electro- 
motive force and inversely with the resistance. 

5. The resistance varies directly with the elec- 
tromotive force and inversely with the current. 

6. The electromotive force varies directly with 
the current and with the resistance. 

This law is the fundamental principle in most 
electric calculations. If thoroughly understood 



ELECTRICAL RULES AND FORMULAS 11 

it will apply in some shape to almost all engineer- 
ing problems. The law will be illustrated by 
examples. 

Single Conductor Closed Circuits. These are 
circuits embracing a continuous conducting path 
with a source of electromotive force included in it 
and hence with a current continually circulating 
through them. 

Example: A battery of resistance 3 ohms and 
electromotive force 1.07 volts sends a current 
through a line of wire of 55 ohms resistance. 
What is the current? 

Answer: The resistance is 3 + 55 = 58 ohms. 
By rule 1 the current is 1.07 + 58, which gives 
.01845 of an ampere. 

A point to be noticed here is that whatever is 
included in a circuit forms a portion of it and its 
resistance must be included therein. Hence the 
resistance of the battery has to be taken into 
account. The resistance of a battery or gener- 
ator is sometimes called internal resistance to dis- 
tinguish it from the resistance of the outer circuit, 
called external resistance. Resistance in general 
is denoted by R, electromotive force or voltage by 
E, and current by C. 



BATTERIES 

A battery is rated by the resistance and electro- 
motive force of a single cell. In the case of 
storage batteries, whose susceptibility to polari- 
zation is very slight, the resistance is often 
assumed to be negligible. 

There are two resistances ordinarily to be con- 
sidered, the resistance of the battery which is 
designated by R or by n times R if the number 
of cells is to be implied and the resistance of the 
external circuit which is designated by r. 

The current given by a battery is equal to its 
electromotive force divided by the sum of the 
external and internal resistance, that is 

Example: A battery of 5 cells arranged to 
give 7,5 volts, with an internal resistance of 10 
ohms, sends a current through a conductor of 12 
ohms resistance. What is the strength of the 
current? 

Answer: Current = 7.5 * (10 4- 12) = .34 of an 
ampere. 

Arrangement of Battery Cells. In practice the 
cells of a battery are arranged in one of three 
ways. All may be in series, all may be in paral- 
lel, some may be in series and some in parallel, 
so as to represent a rectangle. 

12 



BATTERIES 13 

Other arrangements are possible. Thus the 
cells may represent a triangle, beginning with 
one cell, followed by two in parallel and these by 
three in parallel and so on. This and similar 
types of arrangement are very unusual and little 
or nothing is to be gained by them. 

The electromotive force of a battery is equal to 
the voltage of a single cell, multiplied by the 
number of cells in series. 

The resistance of a battery is equal to the 
number of its cells in series, multiplied by the 
resistance of a single cell and divided by the num- 
ber of its cells in parallel. 

Example : A battery of 50 gravity cells 1 volt, 
3 ohms each is arranged 10 in parallel and 5 in 
series. What is its resistance and electromotive 
force? 

Answer: Resistance =5x3^-10= 1.5 ohms. 
Voltage = 5x1 = 5 volts. 

The same battery is arranged all in parallel, 
what is its resistance and voltage? 

Answer: This gives one cell in series. 

Resistance = 1 x 3 -s- 50 = .06 ohm. 

Voltnge =1x1 = 1 volt. 

The same battery is arranged all in series, what 
is its resistance and voltage? 

Answer: This gives one cell in parallel. 

Resistance = — — - = 150 ohms. 
Voltage = 50 x 1 = 50 volts. 



14 THE ELECTRO-PLATERS HAND-BOOK 

The current given by a battery is obtained from 
these rules and from Ohm's law. 

As the difference between these arrangements 
can be more clearly shown by illustrations than by 
a voluminous description, diagrams are here 
given to illustrate the different arrangements. 
At A in Figure 1 the cells are shown arranged in 
series, the zinc in one cell being connected to the 
carbon of the next, and so on through the whole 
line of cells. By this arrangement the electro- 
motive force or power of each cell is added to 
that of its neighbor, and the internal resistance 
of each cell is added in a similar manner. But 
only the v*olume of current generated in one cell 
is had. This is shown by the following figures, 
calculated according to Ohm's law. Supposing 
the electromotive force of each cell to be 1.80 
volts, and the interal resistance of each cell 0.06 
ohms, then, taking three cells in series, the fig- 
ures will be : 

1.80 + 1.80 + 1.80 = 5.40 volts on 

0.06 + 0.06 + 0.06 = 0.18 ohms = 3 ° ampereS ' 

But, if only one cell is taken, the figures will be: 

1.80 volts 



0.06 ohms 



= 30 amperes. 



The difference being, in the first case a current 
of 30 amperes at a pressure of 5.40 volts, while 
in the second case the same current of 30 amperes, 
but at a pressure of only 1.80 volts. At B in 
Figure 1 the cells are shown arranged in parallel, 
the zincs being all coupled to one conductor, and 



BATTERIES 



15 



the carbons to the other conductor of the circuit. 
By this arrangement the three cells are in a corn- 




Fig. 1. Arrangement of Battery Cells. 

bination equal to one large cell, and get the elec- 
tromotive force voltage of one cell divided by 
one-third of its resistance, since there are now 



16 THE ELECTRO-PLATERS HAND-BOOK 

three paths of equal resistance open to the pass- 
age of the current. The figures therefore are : 

0.06-.3 = 0.0* = 90ampereS ' 

with a voltage of only 1.80 volts. When the 
external resistance of the circuit is added to the 
internal resistance of the battery, far different 
results of a more practical value are given. Sup- 
posing, for instance, that the resistance of solu- 
tion, slinging wires, and leading wires amount to 
the total of 1 ohm, then the figures will be, in 
the first arrangement : 
1.80x3 = 5.40 
0.06x3 + 1.00=1.18 = 4 '° 7 ampereS ' 

While in the second arrangement the following 
result would be given : 

0.02 + 1.00 = ^ amperes. 

This shows how useless it is to couple up cells in 
parallel to a high resistance in the outer circuit, 
such as would be met with in actual plating prac- 
tice. But, if four cells are coupled, as shown at 
in Figure 1, which may be described as coup- 
ling in parallel series, the following results are 
given : 

1.80 x 2 = 3.60 
0.03x2+1.00 = 1.06 " 3 - 39 ampereS - 

Thus, by arranging the cells in groups, in either 
series, parallel, or parallel series, the required 
volume of current through the work is obtained 



BATTERIES 17 

at the voltage suitable to the deposition of the 
metal in a proper condition. It is preferable to 
so arrange the cells, as shown, instead of dividing 
the circuit, or adding resistances to keep back 
the current. 



ELECTROPLATING WITH BATTERIES 



The first experiments in electro-plating were 
carried out with current derived from galvanic 
batteries.- Its application to commercial uses 
was also made by the same means. Some good 
work on a large scale has been done with current 

from batteries. Al- 
though, in large work- 
shops, the battery as 
a generator has been 
quite superseded by 
the dynamo, it still 
retains its place in 
small shops and in the 
home of the amateur 
electro-plater. When 
operations in a small 
way have to be con- 
ducted at intervals in 
small shops where 
power cannot be read- 
ily obtained to drive 
a dynamo, the use of a battery becomes a neces- 
sity, and is a less costly generator than a plating 
dynamo with its accessories. 

Batteries used for electro-plating are of two 
forms, single and double liquid types. In the 
first-mentioned form the elements, which usually 

18 




Fig. 2. Single Liquid Type of 
Plating Battery. 



ELECTRO-PLATING WITH BATTERIES 19 



consist of carbon and zinc plates or cylinders, are 
immersed in the same solution, while in the 
double liquid form the carbon element is in one 
solution in a porous cup in the center of the con- 
taining vessel or jar and the zinc element sur- 
rounds the porous cup in another solution. 

A battery of the single liquid type is shown in 
Figure 2, in which the carbon and zinc elements 
are attached on either 
side of a wooden sup- 
port. To charge this 
form of battery, add 
1 part (by volume) of 
sulphuric acid to 8 
parts of water, when 
cool add 2 parts (by 
weight) of nitrate of 
soda. Chromic acid 
or bichromate of soda 
may be used instead of 
the nitrate of soda as 
a depolarizer, but are 
much more expensive. 

A double liquid type of battery is shown in- 
Figure 3. To properly charge such a battery, 
add 1 part of sulphuric acid to 10 parts of water, 
when cool put in the containing vessel or jar in 
which the zinc element goes. If chromic acid is 
used as the depolarizing agent in the porous cup, 
use 2 parts (by weight) of chromic acid to 10 
parts (by volume) of water. When either bi- 
chromate or nitrate of soda are used, the propor- 




Fig. 3. 



Double Liquid Type of 
Plating Battery. 



20 THE ELECTRO-PLATERS HAND-BOOK 

tions should be as follows: Water 8 parts, 
sulphuric acid 8 parts (by volume), bichromate 
or nitrate of soda (by weight) 2 parts. The zinc 
elements should be kept well amalgamated 
and always removed from the cell when the bat- 
tery is not in use. 

The single liquid type of battery has a voltage 
of from 1.G3 to 1.75 volts per cell, while the 
double liquid battery has a voltage of about 2 
volts per cell. 

The positive pole or carbon of the battery 
should always be connected to the anodes in the 
plating solution and the zinc or negative to the 
cathodes or work being plated. 

Construction of Batteries. The construction of 
batteries for electro-plating must be governed by 
the requirements of the work. These usually 
demand a full, constant current at a low voltage. 
To insure the first condition, large cells must be 
used and have electrodes with a large surface. 
The cells should be not less than one-half gallon 
in size, and may be of ten-gallon size with ad- 
vantage. The electrodes must be large, to cor- 
respond with the cells, but there should be at 
least one inch free space below the plates when 
they are fully immersed. This space being 
necessary to prevent short circuiting and local 
action caused by particles of metal falling from 
the electrodes to the bottom of the cell. It is a 
well-known rule, that the surface of the plates in 
a battery should exceed that of the anodes in the 
depositing solution, and these should present a 



ELECTRO-PLATING WITH BATTERIES 21 

surface slightly in excess of the surface to be 
plated. When the cells are arranged in series, 
only the surface of the electrodes in one cell can 
be taken into account, all the others being em- 
ployed in forcing the current through the resist- 
ance in the circuit. Large cells and large 
electrodes insure a low internal resistance of the 
battery, and consequently more force for use in 
the outer circuit, since the strength of the cur- 
rent will be equal to the voltage of the battery 
divided by all the resistances in the circuit. To 
insure constancy, both the exciting and the de- 
polarizing liquids must be in a condition to work 
through the required time. 

Amalgamation of Zinc. The zinc plates used 
in batteries are rarely made of pure metal. Even 
the best rolled zinc contains impurities. The 
effect of these impurities is seen in local action, 
in which the impure zinc forms with the purer 
particles a number of galvanic pairs. By coating 
the zinc with mercury, this tendency to local 
action is reduced to a minimum. As the zincs 
come from the maker, they are coated with a 
greasy film, unless sent out amalgamated. To 
remove this film, dip the zincs in hot water in 
which some washing soda has been dissolved, and 
rinse them in clean water. Pour some mercury 
in a shallow dish, such as a baking dish or a 
porcelain tray, and cover the mercury with a 
mixture of sulphuric acid and water, made by 
adding 1 part by measure of sulphuric acid to 3 
or 4 parts by measure of water. Some caution is 



22 THE ELECTRO-PLATERS HAND-BOOK 

always required when adding this acid to water, 
as the acid combines with the water in such a 
violent manner as to cause great heat and spurt- 
ing of the mixture. The consequences might be 
serious damage to skin and to clothing, as the 
acid is very corrosive and will quickly destroy 
clothing. Therefore, always add acid to the 
water slowly, but never add water to the acid. 

Place the zincs in the dilute acid and brush the 
mercury all over their surface with a brush made 
of fine steel wires, until all the surface has been 
made bright with the mercury. Then set the 
zincs aside in an empty dish to drain off the sur- 
plus mercury. Zincs must be reamalgamated in 
a similar manner when any part of them have lost 
their coat of mercury, and bare gray patches 
appear on them whilst being cleaned. A wide 
bristle brush will be found a very useful article 
for brushing zincs after use in the battery. 
When zinc cylinders are used, the insides must 
receive the most attention, as these are the parts 
subject to the action of the acid. Set the zkres 
in empty jars when not in use, to catch the mer- 
cury draining from them, 



ELECTRO-PLATING DYNAMOS 

The evolution of the dynamo may be said to 
date from the time when it was discovered that 
an electric current passing through a coil of wire 
produced an inductive effect on a magnetic needle 
placed beneath it, or, in other words, an electric 
current passing through a wire exerted mag- 
netic effects on iron and steel placed near the 
wire. This discovery led Michael Faraday, in 
1831, to infer that, since a magnetic effect could 
be produced in iron by a current of electricity, a 
magnetized piece of steel in motion should pro- 
duce an electric current. A long spiral or helix 
of copper wire was therefore procured and its 
ends connected with a galvanometer. A power- 
ful bar magnet was then introduced into the 
spiral of wire. This being done, a deflection of 
the galvanometer needle took place instantly 
when the bar magnet was placed in the coil, and 
an opposite deflection was caused when the mag- 
net was withdrawn. This discovery led to the 
construction of a machine in which a disc of cop- 
per connected by wires to a galvanometer was 
caused to revolve between the poles of a power- 
ful horse-shoe magnet, and thus set up a current 
of electricity in the wire. Other experimenters fol- 
lowed on the same lines, and in the course of a few 
years the magneto-electric machine was so far de- 

23 



24 THE ELECTRO-PLATERS HAND-BOOK 

veloped as to produce brilliant sparks, give power- 
ful shocks, and also effect chemical decomposition. 
Principle of a Dynamo. A dynamo-electric 
machine is a machine constructed to convert 
dynamic or mechanical force into electric energy. 
It has been already shown that a moving bar 
magnet will induce a current of electricity in a 
helix of copper wire surrounding the magnet. 
The influence of a magnet is not only felt in a 
wire wrapped around its poles, but extends to a 
considerable distance beyond them. In the case 
of a horse-shoe magnet the magnetic influence 
fills the space between the poles, and extends 
beyond them. This space, thus filled with mag- 
netic lines of force, is called the magnetic field. 
If some turns of insulated copper wire are wrapped 
around a bar of iron, and it is caused to move in 
this magnetic field so as to cut the lines of force, 
a current of electricity will be induced in the 
turns of wire wound on the iron bar, by the cut- 
ting of the lines of magnetic force through which 
it moves. If some insulated copper wire be wound 
around the legs of the magnet, a current of elec- 
tricity will be set up in the magnet coils as well 
as in the coils of wire surrounding the iron bar. 
It may be mentioned that in the field of a horse- 
shoe magnet there is a neutral zone in which 
there are few lines of magnetic force to be cut by 
the moving bar. It follows, therefore, that the 
electric inductive influence of the magnet on the 
armature coils will be greatest where the lines of 
force cut are the most dense. As the armature 



ELECTRO-PLATING DYNAMOS 25 

is made to move in the magnetic field, there will 
be two strong magnetic impulses and two re- 
versals. If the ends of the armature coil are 
connected with the ends of the magnet coil so as 
to send the strong impulses through this coil in 
one continuous direction, the effect of this current 
of electricity flowing through the magnet coils 
will be an increase of magnetic strength in the 
magnet. This is done in a dynamo by means of 
a device known as a commutator. A commu- 
tator is made in the form of a split ring of brass 
mounted on an insulated hub, and fixed on the 
shaft of the armature. The two ends of the 
armature coils are connected with the two sec- 
tions of the commutator, and the current is col- 
lected from these by two strips of metal called 
brushes. In some armatures there are several 
coils. When this is the case, the commutator 
has as many segments as there are coil ends, but 
the action is the same. As the coil of wire passes 
out from the most intense part of the magnetic 
field into the comparatively neutral zone, the 
impulse given to it is interrupted by a division in 
the commutator, and diverted by way of the 
brush to the magnet coil or to the outer field. 
In this way a current of electricity is generated 
by the rotation of the armature in the coils of 
wire wound on it and also on the field magnets, and 
the machine thus becomes a generator of electricity. 
Selecting a Plating Dynamo. The resistance of 
the plating solution, the slinging wires, and the 
wires conducting the current from the dynamo to 



26 THE ELECTRO-PLATERS HAND-BOOK 

the vat being known, the armature of the dynamo 
should be wound with wire offering a resistance 
of one-twentieth the working resistance of the 
outer circuit. The field magnets should be 
wound with wire having a total resistance of 400 
times that of the armature, or 20 times the total 
resistance of the outer circuit. The armature 
coils should be connected in shunt with the coils 
of the field magnets, to insure uniformity of the 
current under varying loads, and to prevent re- 
versal of the magnetism in the dynamo by the 
current being sent through the field magnet coils 
in the wrong direction. It should be understood 
that all solutions, through which a current has 
been passing, form in themselves a galvanic bat- 
tery, with the articles being plated and the anodes 
as elements. The plated articles being the posi- 
tive elements, and the anodes the negative ele- 
ments, in this galvanic battery, the current 
generated is therefore opposite to that employed 
in the work of electro-plating. If the coils of 
the field magnets of a dynamo are connected in 
series with those of the armature and the outer 
circuit, the back current from the solution will 
rush around the coils immediately after stopping 
the dynamo, or on slowing down its speed, and 
will reverse the poles of the field magnets by 
inducing in them an opposite condition of mag- 
netism to that existing while the dynamo is in 
proper working order. This is prevented by con- 
necting the field magnet coils in shunt with the 
armature, and should the back current from the 



ELECTRO-PLATING DYNAMOS 27 

solution become sufficiently powerful to pass 
round the field magnet coils, it passes through 
them in the same direction as it is sent by the 
dynamo itself, and does not reverse the permanent 
magnetism of the field magnets. 

In a dynamo wound for electro-plating, with 
the coils connected in shunt, the magnetism of 
the field magnet cores will be proportionate to 
the resistance in the outer circuit. If there are 
several articles suspended in the solution, and a 
proportionate surface of anode, the resistance of 
the outer circuit will be low, and the greater 
volume of current will flow by the path offering 
least resistance, which will be, in this case, 
through the solution. As a consequence, only a 
small portion of the current will pass around the 
field magnet coils, and thus the magnetic in- 
tensity of the fields will be low. If, on the con- 
trary, the resistance in the plating vat is high, 
when only a few articles are immersed in the 
solution, the path of least resistance will be by 
way of the field magnet coils, the armature cur- 
rent will flow by this path, increase the intensity 
of the magnetic field, and raise the tension of the 
current, thus enabling it to overcome the in- 
creased resistance in the plating vat. 

Choice of a Dynamo. In the early days of plat- 
ing dynamos for electro-deposition, the makers 
were few and far between. At the present time 
almost any maker of dynamos can make a ma- 
chine for electro-deposition. In choosing a new 
dynamo, see that it is shunt wound, that is, that 



28 THE ELECTRO-PLATERS HAND-BOOK 

the wires from the field magnet coils are con- 
nected one to each brush, and that the terminals 
which lead to the outer circuit are also connected 
one to each brush. Although the series machine 
is cheaper to operate for a given output, yet it is 
sure to be subject to reversal sooner or later. 
Mechanical devices are in use to prevent the in- 
jurious back flow of the current from the vat, but 
these are not always reliable. Compound wound 
machines, which possess both shunt and .series 
coils, are equally liable to reversal, but these 
machines are very suitable for special work re- 
quiring a constant low voltage through varying 
resistances in vats connected in parallel with the 
dynamo. The output of the dynamo should be 
expressed in amperes, but some makers express the 
output by so many square feet of exposed cathode 
surface, thus giving the plater some idea of the 
surface of goods he can cover at the same time. 
The dynamo chosen should have a broad, firm 
base, so as to stand steady while running. Its 
bearings should be long, and provided with means 
to keep them well lubricated, to prevent heating 
while at work. It must be well ventilated by air 
spaces between the coils, to keep them cool while 
the machine is working. Heating of the coils 
and bearings means a loss of power in the outer 
circuit, and a loss of driving power, since heat 
absorbs the force which should be converted into 
electricity. The driving pulleys should have 
broad, smooth surfaces, to prevent loss of power 
by slipping belts, and the machine should be 



ELECTRO-PLATING DYNAMOS 



29 



driven from a countershaft. All wearing parts 
should be so arranged as to be easily got at and 
removed for repair. This applies specially to the 
brushes, brush-holders, and commutator. The 
brush-holders should not be fixed to any part of 
the machine, but should be attached to a rocker 
arm, pivoted in such a manner as to allow of free 
movement through an arc of a circle, for the easy 



J <] 




Fig. 4. Plating Dynamo of the Weston Type. 



adjustment of the brushes to any angle. The 
commutator segments should be of hard copper. 
The brushes may be of carbon or fine copper 
gauze. The brush-holders should be pivoted on 
the rocker arm and furnished with springs to 
exert an equal pressure on the brushes. 

Plating Dynamo. A plating dynamo of the 
Weston type is illustrated in Figure 4. These 



30 THE ELECTRO-PLATERS HAND-BOOK 

dynamos may be either shunt or compound wound. 
The frame and pole pieces are of cast steel. For 
the frame a special soft grade is used, having a 
high magnetic permeability. The field coils are 
made of insulated copper wire wound compactly 
by machinery, insuring the maximum ampere 
turns without great bulk. The whole coil is 
properly insulated and protected from mechanical 
injury. The armature is of the toothed type and 
is most carefully constructed. The core is built 
up of thin soft steel discs. Each disc is insulated 
on both sides and assembled on a spider con- 
structed to insure the greatest amount of venti- 
lation. 

The armature coils are made in a form and per- 
fectly insulated. The slots in which the coils 
rest are also insulated, so there is no chance for a 
ground. 

The segments of the commutator are forged 
from pure copper carefully insulated with the best 
mica. The radials from the bars are so arranged 
that a steady current of air is thrown on the com- 
mutator and brushes. 

The bearings are self-aligning, and the boxes 
made of special bronze, and provided with large 
oil wells and automatic oiling rings. 

These machines are said to run continuously 
under full load with a rise of temperature above 
the surrounding atmosphere not exceeding 8 
degrees Centigrade (46 degrees Fahrenheit) in 
windings, and somewhat less in the commuta- 
tor. The commercial efficiency is said to be 



ELECTRO-PLATING DYNAMOS 31 

85 per cent, and the electrical efficiency 93 per 
cent. 

Compound versus Shunt Wound Plating Dyna- 
mos. A little information as to the merits of 
compound as opposed to shunt winding may not 
be out of place. The shunt wound dynamo has 
only one winding on its field magnets, in which 
only a portion of the current generated passes 
through the field winding and in operation will 
lower its voltage as the tanks are filled with work, 
while the brushes have a tendency to spark on 
the commutator, which necessitates their regula- 
tion from time to time as the load increases or 
decreases. 

These particularly undesirable features are due 
to the method of winding of a shunt wound 
dynamo, which permits only a small portion of 
the current generated by the armature to pass 
through the field coils, while at the same time the 
armature reaction is constantly tending to reduce 
the field magnetism, which in many types of shunt 
wound machines makes necessary an exciter in 
the shape of a small dynamo, in order that the 
fields may be properly charged. This current 
from the exciter must be regulated as the load on 
the dynamo is increased or diminished. 

Under these conditions more time must be con- 
sumed in plating a given batch of work than 
would be necessary if the dynamo was of com- 
pound type, while the sparking of the brushes on 
the commutator as load is increased or decreased 
requires frequent renewal of the latter. 



32 THE ELECTRO-PLATERS HAND-BOOK 

In the plating room where there are a number 
of tanks containing different solutions of varying 
densities, or of solutions requiring a difference in 
voltage for the successful production of work, 
the disadvantage of a shunt machine is apparent 
for the reason that when a tank is emptied and so 
much load is taken from the machine, the voltage 
will increase in all the other tanks, thus making 
necessary a constant watchfulness on the part of 
each man in charge of a tank, or work may be 
burned. There are other disadvantages which 
always apply to the shunt wound type of 
dynamo. 

Compound Wound Plating Dynamo. A com- 
pound wound dynamo has two distinct windings 
en its field magnets, one of very many turns of 
fine wire, called the shunt winding, and another 
known as the series winding, which latter con- 
sists of a number of turns of heavier gauge wire. 
The series winding is in series with the T?ats or 
external circuit. The current that is used in the 
vats, passing through this winding, increases the 
magnetism of the field as the load increases, and 
thus the drop in voltage, which would otherwise 
occur by reason of the increased drop in the 
armature winding and increased magnetic reac- 
tion caused by the armature current, is provided 
for. 

Speed of Plating Dynamos. Plating dynamos 
are built to run at lower speeds than electric 
lighting dynamos, because the voltage of a plat- 
ing current is lower than that employed for elec- 



ELECTRO-PLATING DYNAMOS 33 

trie lighting. The voltage of the current from a 
dynamo largely depends upon the speed of its 
armature. As each yard of active wire on an 
armature coil is capable of developing one volt 
when driven at a circumferential velocity of 
1,250 feet per minute, the voltage of the current 
from a dynamo may be readily calculated if the 
length of the active wire on one of its armature 
coils and the speed at which the armature is 
driven be known. The circumferential velocity 
of the armature may be ascertained by measuring 
its diameter, multiplying this by 3.14 to find the 
circumference, and then by the speed of the 
armature. To increase the voltage of the cur- 
rent from a machine its speed must be increased, 
and to lower the voltage the speed must be de- 
creased. Plating dynamos are usually driven at 
speeds varying from 700 to 1,500 revolutions per 
minute. The speed can be ascertained by count- 
ing the revolutions of the driving pulley and cal- 
culating the speed of the pulley driven by it, or the 
speed of the armature shaft may be taken direct 
by means of a speed indicator. 

Dynamos, Efficiency of. The limit of efficiency 
of a dynamo is at the point where the voltage or 
pressure ceases to be strong enough to deposit 
metal to the best advantage. In shunt wound 
machines the voltage usually drops below the 
desired pressure when from one-half to two-thirds 
of the ampere capacity is being taken out. Com- 
pound wound dynamos will maintain the same 
pressure up to the full rated capacity of their 



34 THE ELECTRO-PLATERS HAND-BOOK 

amperage, and it is for this reason that from 
compound wound dynamos an efficiency of from 
one-third to one-half more can be obtained over 
shunt wound machines of the same rated 
capacity. 



ELECTRO-PLATERS MATERIALS 

In a well organized electro-plater's shop there 
are many appliances necessary besides plating bat- 
teries and dynamos for properly performing the 
work. Some of these are necessaries, without 
which not even the most simple operation may be 
done, while others may be termed conveniences 
for facilitating larger operations or work of a 
more intricate nature. Platers working even in 
the smallest way with a plating battery must have 
suitable vessels for holding the plating solutions 
and the various pickles used in preparing the 
work. Slinging wires are necessary for holding 
the articles in the solutions, and suitable brushes 
for cleaning the work before being plated and 
finishing its surface afterwards. Among con- 
veniences may be mentioned a selection of revolv- 
ing scratch brushes, and a lathe for revolving 
them, a similar selection of small polishing 
wheels, made of different materials, and denomi- 
nated dollies, mops, bobs, etc.. together with a 
suitable machine for working them, a set of hand 
brushes for cleaning and polishing, and a set of 
burnishers if silver and gold plating is to be 
done. 

Plating Vats. Although the outer containing 
box is made of strong wood with well-fitting 
joints, this material alone is not suitable for plat- 

35 



36 THE ELECTRO-PLATERS HAND-BOOK 

ing solutions, since the wood absorbs a large 
quantity of the solution, and the salts creep over 
the sides. The frame must therefore be lined 
with a material impervious to the speedy action 
of the cyanide, such as a coating of asphaltum, 
but better yet is sheet lead, this will resist the 
action of the cyanide for many years, but all 
joints must be made by burning instead of solder- 




Nickel-plating Tank. 



ing, as solder will form with lead a galvanic pair, 
and a galvanic action will soon corrode the joints. 
The lead-lined tank must then be lined with 
match-board, to prevent the accidental contact 
of the articles with the lead lining, and the upper 
rim of the vat should be framed with strips of 
wood boiled in paraffine, to prevent the internal 
absorption and creeping of the salts. 



ELECTRO-PLATERS MATERIALS 



37 



Plating vats should be selected with a view to 
the magnitude of the operations to be performed 
in them. If the operator desires to plate a few 
rings, scarfpins, brooches, studs, sleeve-links, 
solitaires, and similar small articles, a suitable 
vat is an enameled iron saucepan holding from 
one to two pints of liquid, or a stoneware salt- jar 
immersed in hot water in a saucepan, but if 




Fig. 6. Group of Plating Tanks. 

watch-chains, watch-cases, and similar longer or 
more bulky goods are to be plated, a larger pan 
or vat must be obtained. If the operations are to 
be extended to a larger trade, a larger enameled 
iron vat, capable of holding from five to ten gal- 
lons, will be required, and this must be heated 
over a suitable furnace, or over an atmospheric 
gas-burner, or by means of a steam-jacket. The 
two last means are preferable, as being more 



38 THE ELECTRO-PLATERS HAND-BOOK 

under control than the first. It must be under- 
stood at first, that the vat for gold-plating solu- 
tions must be impervious to the attacks of potas- 
sium cyanide when heated to a temperature of 
from 150 to 180 degrees Fahrenheit. All metals 
except platinum are soluble in hot cyanide solu- 
tions, and nearly all other substances, except 
glass, vitrified stoneware and enameled iron. 




Fig. 7. Glazed Stoneware Tank. 



Figures 5 and 6 show different styles of plating 
vats. 

Plating tanks for very large work are usually 
made of wood and lined with a thick coating of 
asphaltum. ... 

Tanks. Tanks for use with acid should be of 
glass or glazed stoneware, enameled wrought iron 
tanks are more suitable for potash and alkaline 
solutions. : * A heavy glazed stoneware tank is 
shown in Figure 7. For small work a good 



ELECTRO-PLATERS MATERIALS 



39 



quality of white enameled iron cooking utensil 
may be used for the potash solution. 

Heating Tanks. Large tanks for heavy work 
are usually made of cast iron and heated by a 
steam coil in the bottom of the tank. Such tanks 
are used for solutions that must be kept hot, 
Such as lye, rinsing water, cleaning compound 
and cyanide solutions. These tanks, along with 




Fig. 8. 



Steam Tanks with Coils in the Bottom of the 
Tank. 



the steam chamber, are cast in one piece. A pair 
of the tanks are illustrated in Figure 8 in posi- 
tion and ready for use. 

Another form of steam tank or kettle is illus- 
trated in Figure 9. A positive circulation of 
steam is carried through the channels shown in 
the drawing in the bottom of the tank. These 



40 THE ELECTRO-PLATERS HAND-BOOK 

are extra tanks and adapted for use wherever lye, 
cleaning compound, water or alkaline solutions 
are to be kept constantly hot. 




Fig. 9. Steam Kettle with Corrugated Steam Passages. 




Fig. 10. Glazed Stoneware Dipping Baskets. 

Dipping Baskets. Baskets of glazed stoneware 
are always used when a number of small articles 
have to be dipped in acid or cyanide solutions, 



ELECTRO-PLATERS MATERIALS 41 




Fig. 11. Steel or Aluminum Wire Dipping Baskets- 



42 THE ELECTRO-PLATERS HAND-BOOK 



As successful dipping depends more upon quick 
and careful handling than upon the nature of the 

dip itself, the 
holes in these 
baskets should 
be as large 
as possible, to 
allow of the 
rapid escape of 
the acid or 
cyanide. Three forms of glazed stoneware 
dipping baskets are illustrated in Figure 10. 
Woven wire baskets of round or square shape are 
also used for dipping purposes. They are made 
of brass, steel or aluminum. Ten different styles 
of these baskets 




Fig. 12. Potash Hand-brush. 



are 



m 



shown 
Figure 11. 

Scouring 
Brushes. When 
articles are be- 
ing cleaned in 
alkaline solu- 
tions to remove 
grease, brushes 
made of animal 
fiber cannot be 
used, as it would 
be eaten away 
by the solution. 
For this purpose brushes known as potash brushes 
are used. They are made of hard wood backs fitted 




Fig. 13. Potash Brushes. 



ELECTRO-PLATERS MATERIALS 



43 



with knots or tufts of cotton or other vegetable 
fiber. Some of the many kinds of brushes used 
for this work are shown in Figures 12 and 13. 
Brushes used for scouring the work with are 
illustrated in Figure 14. They are of three 
forms, as shown, having flat, curved and shoe 
handles to suit different conditions of work. 




Fig. 14. Scouring Brushes. 

They are made with either brass, steel or fiber 
bristles. 

Scratch-Brushes. Brushes intended for the 
general work of cleaning large surfaces are made 
of brass or steel wire, and of various degrees of 
softness according to the gauge of the wire used. 
These brushes are fitted with wooden hubs, with 



44 THE ELECTRO-PLATERS HAND-BOOK 



a hole in the center to fit the spindle of the 
lathe. Three different forms of scratch-brushes 
are shown in Figure 15. The one shown in the 

upper view is 
for flat work 
and the two 
brushes shown 
in the lower 
view for cup 
and goblet work 
especially. For 
smaller articles, 
such as thimbles 
and rings, the 
brushes shown 
in Figure 16 are 
better adapted, 
especially for 
inside work. 

Scratch-Brush 
Lathes. A com- 
bination foot- 
power lathe for 
use with either 
small buffing 
wheels or 
scratch -brushes 
is shown in 
Figure 17. For 
small jobs these lathes will be found well adapted. 
A power combination bench lathe is shown in 
Figure 18, 




Fig. 15. Scratch-brushes for Flat, Cup 
and Goblet Work. 



ELECTRO-PLATERS MATERIALS 



45 




Fig. 16. 



Scratch-brushes for Thimbles 
and Rings. 



Dust-Brushes. For removing dust from highly 
polished gold or silver plated articles, after being 
dried in hot 
sawdust, the 
brushes shown 
in Figure 19 are 
well adapted, as 
they are made 
of camel ' s 
hair. 

Polishing 
Wheels. Wheels 
or bulls used 
for polishing 
articles may be 
divided into 
two classes, 
those for pre- 
paring the sur- 
faces to be 
plated and 
those for finish- 
ing or giving 
the final polish- 
ing during the 
plating opera- 
tion. Various 
forms of pol- 
ishing wheels 
and buffs are 

shown in Fig- 
Fig. 17. Foot-power Scratch-brush 
ure 20. Lathe. 



$fit 






9 





46 THE ELECTRO-PLATERS HAND-BOOK 



Polishing Wheels, Directions for Using. Screw 
on the spindle only tight enough to hold in place. 
If there is any nutter or side motion, some- 
times caused by careless handling or screwing 

too tight, it can 
be remedied by 
side pressure of 
the hand, or 
by loosening or 
tightening the 
nut on the spin- 
dle. Always 
remember to use 
care the first 

Fig. 18. Power Bench Scratch-brush tim0 m settm o 

Lathe. the wheel. 







Fi£. 19. Camel Hair Dust Brushes. 



ELECTRO-PLATERS MATERIALS 



47 



Run in direction indicated by the arrow on 
the face. 

Soft and medium for silver, nickel work, 
brass, etc. 

Medium for stove, axe, or plow work, and 
saddlery hardware. 

Hard for gold, brass, emery hard grinding, and 
for grease or oil work. 




Fig. 20. Polishing Wheels. 



Polishing Wheels, Balancing of. All wheels 
running as fast as they must in polishing, require 
to be very carefully balanced or they will pound 
or chatter, making good work impossible. 
Balancing is accomplished by placing the wheel 



48 THE ELECTRO-PLATERS HAND-BOOK 

on an arbor and rolling it on two level, knife- 
edged strips of metal, one on each side of the 
wheel. Thns suspended the wheel will stop with 
its heaviest part downward, and with a little 
chalk to mark the wheel and some small pieces of 
sheet lead to fasten on the side of the wheel, bal- 
ancing is quickly and easily performed. It may 
also be done by hanging the arbor between cone 
centers, as pulleys are balanced in a machine 
shop, but the rolling method of balancing en 
bars, which is precisely the method the watch- 
maker employs in poising a watch balance, is the 
quickest and best. 

Leather wheels are used in polishing and fine 
grinding, where a flexible wheel is necessary. 
There are many different kinds of wheels which 
may be classed under this head. 

Walrus wheels are made from the tanned hide 
of the walrus, and are used for work requiring 
the wheel to be turned up to a thin, moulded 
edge or curve, as they are thick enough to allow 
such shapes to be made from a single piece. 

Bull neck wheels are made from the thickest 
and toughest portions of hides, and form a 
harder wheel than walrus. They are much used 
in stove, bicycle and other steel and iron work. 
Other leather wheels are similar in their nature, 
differing only in the mechanical structure and 
degree of hardness, the desirable quality being 
the ability to hold the emery up to the work 
without allowing any lumps or unevenness in the 
glued emery to cut into or gouge the work. 



ELECTRO-PLATERS MATERIALS 49 

Felt wheels are used with emery and glue, or 
with polishing compositions. They are of vary- 
ing degrees of hardness and either white or gray. 
The higher-priced felt wheels are the cheapest in 
the end, the extra price being more than made 
up in the increased durability and uniformity of 
the white wheels, which wear much longer, and 
give a superior finish, than do the cheaper gray 
felt wheels. 

Cotton buffs are made of discs of muslin and 
are used with pastes of tripoli, crocus or rouge 
for finishing or coloring. The hardest buffs are 
made in sections, from duck, stitched or quilted 
together, while the soft buffs are muslin stitched 
only at the center. As many sections as may be 
necessary to make the desired thickness of wheel 
are put on the arbor and the flanges set up until 
the wheel runs properly. 

Canvas wheels are made of coarse duck or can- 
vas, cut into discs of the required size and glued 
or cemented together under pressure, after which 
they are bored out to receive the arbor, put on the 
machine and turned up to the required shape. 

Emery or corundum wheels are used for grind- 
ing off the imperfections on castings caused by 
breaks in the moulds. These wheels are of vary- 
ing thicknesses, grades, sizes and shapes and 
should be run at correspondingly varied speeds 
in order to get the best results out of them. If 
run too fast th^y will glaze and require frequent 
dressing to keep them sharp. Too much pressure 
when grinding will also glaze a wheel. 



50 THE ELECTRO-PLATERS HAND-BOOK 

Polishing Lathes. Polishing lathes are, as a 
rule, made much heavier and stronger than 
scratch-brush lathes, and have massive cast iron 
pedestals and extra long hearings so as to stand 
heavy work at high speeds. The spindles are 
fitted at their outer ends with screw threads, col- 
lars and lock-nuts for clamping the wheels upon 




Fig. 21. Extra Heavy Polishing Lathe. 

them. The work of polishing is best done when 
the spindle is driven at a high rate of speed, t.s 
the greater the surface velocity of the wheel cr 
buff, the better and quicker the finish is imparted 
to the surface of the work. 

An extra heavy polishing lathe is shown in Fig- 



ELECTRO-PLATERS MATERIALS 51 

ure 21, and various forms of spindles for use in 
the same are illustrated in Figure 22. 




Fig. 22. Spindles for Heavy Polishing Lathe. 

Polishing Materials. The materials in use for 
polishing metals to prepare them for plating are : 
Finely prepared and sifted sand, lime, rotten 
stone, pumice stone, and various compositions of 



52 THE ELECTRO-PLATERS HAND-BOOK 

emery, crocus, tripoli, and rouge for imparting a 
high state of finish to the articles. Tripoli, 
crocus, and rouge, in Yarious grades to suit the 
work, are made up into cakes or bars. In this 
form it gives less trouble, and makes less waste 
than when used in the form of loose powder. 
The cake of composition is pressed against the 
wheel or buff whilst it revolves, which then 
becomes charged with the abrading material and 
holds it whilst the woik of polishing is being 
done. Tripoli is used in the rough on leather 
wheels for preparing brass work. The fine tripoli 
is used on calico buffs for imparting a high finish 
on brass, copper or steel before it is plated, and 
in finishing nickel-plated work. Crocus is used 
for a similar purpose. Rouge composition is 
used to impart a high state of finish to jewelry, 
spoons, forks, and electro-plated goods. Pumice 
stone in fine powder, and rotten stone, are used 
in scouring goods by hand with brashes in the 
scouring trough. Pumice stone in lumps, and 
rotten stone, are both employed as abrading 
materials to rub down by hand, rough, pitted and 
corroded surfaces in places difficult to be got at 
with wheels or buffs. 

Tripoli comes in three grades : Coarse, for cut- 
ting down rough or hard brass or bronze on hard 
buffs. Medium, which is used on medium buffs 
for smoothing and cutting down softer metals. 
Fine, which is used on soft buffs for coloring 
on cheap work and for use in place of the 
harder rouges where the color of the latter is 



ELECTRO-PLATERS MATERIALS 53 

objectionable anl is difficult to get out of the 
work. 

Lime. The lime used for polishing is a pure 
anhydrous lime, obtained from Vienna, and is ex- 
tensively used where the red color of rouge is 
objectionable. It must be used while slacking 
or it is of no value, so it must be kept in 
the airtight tin or bottle in which it was 
shipped. 

Rouge. This polishing material is used for 
coloring brass, gold, silver and the softer metals. 
It is divided into numerous grades, which are dis- 
tinguished by the names of the metals for which 
they are used. 

Crocus. This substance is an oxide of iron, 
made by calcining sulphate of iron in great heat 
and then grading it into polishing powders. The 
more calcined part is of a bluish purple color, 
coarser and harder than those portions which 
have been exposed to a lesser heat, and is called 
crocus, while the softer and redder portions of 
the material are called rouge. 

Pumice Stone. This material is described as a 
highly porous, light mineral substance of volcanic 
origin, resulting from the solidification of foam or 
scum formed by the escape of steam or gas on the 
surface of molten lava, and is composed of 72 per 
cent of silica, 17 per cent of alumina, 2 per cent 
of iron oxide, and 9 per cent of soda and 
potash. 

Pumice stone is used in powdered form for 
scouring the work, to remove all traces of oil, 



54 THE ELECTRO-PLATERS HAND-BOOK 

grease or lye, just before putting the work in the 
plating solution, also in lumps, for scouring spots 
that refuse to take the plating, which is a com- 
mon fault in replating old goblets, cups and trays 
that have been badly corroded. 

Speed of Wheels. The peripheral speed or cir- 
cumferential velocity of a polishing wheel or buff 
should not exceed a maximum velocity of 100 
feet per second, or a minimum velocity of less 
than 70 feet per second, if good work is expected 
from the wheel or buff. As the wheels or buffs 
wear down the work proceeds slower and slower, 
unless cone pulleys are provided on the line shaft 
and the countershaft of the polishing lathe. 
The accompanying table gives the maximum and 
minimum speeds for wheels from 1 to 36 inches 
in diameter, in revolutions per minute. 

Speed op Wheels in Revolutions per Minute. 



%£ 


Revolutions per 




Revolutions per 


©■g 


Minute. 


S.-g 


Minute. 


03M 




















5.2 


Minimum. 


Maximum. 


Q.B 


Minimum. 


Maximum. 


1 


13,000 


18,000 


9 


1,760 


2,460 


11 


10,000 


14,000 


10 


1,580 


2,210 


2 


7,900 


11,000 


12 


1,320 


1,850 


21 


6,330 


8,800 


14 


1,130 


1,580 


3 


5,275 


7,400 


16 


990 


1,380 


3* 


4,500 


6,300 


18 


880 


1,230 


4 


3,950 


5,500 


20 


790 


1,100 


41 


3,500 


4,900 


22 


720 


1,000 


5 


3,160 


4 S 400 


24 


660 


920 


6 


2,640 


3,700 


26 


600 


850 


7 


2,260 


3,160 


30 


500 


735 


8 


1,980 


2,770 


36 


400 


585 



ELECTRO-PLATERS MATERIALS 



55 



Wheel Truing Device. A wheel truing device 
for balancing polishing wheels of all kinds, iron 
pulleys or emery- 
wheels, is shown 
in the upper 
view in Figure 
23. The cones 
will take four 
sizes of arbors, 
and are usually 
furnished with 
the machine. 

Wheel Clean- 
ing Machine. A 
wheel cleaning 
machine is illus- 
trated in the 
lower view in 
Figure 23. By 
placing the worn 
wheel in this 




Fig. 23. Wheel Truing Device and 
Wheel Cleaning Machine. 



machine, and letting it run a few minutes with 
the water just touching the rollers, all of the 
glue and emery will be removed without damag- 
ing or loosening the leather covering. 

This machine has two rows of movable rods to 
keep the wheels from falling over. The idle 
roller also has two positions for different diam- 
eters of wheels. The speed of the machine 
should be about 20 revolutions per minute. 

Belt Straps are made of canvas or duck, from 
one to two inches wide, glued and set up with 



56 THE ELECTRO-PLATERS HAND-BOOK 

emery as previously described, and used in polish- 
ing flat surfaces, such as cutlery, flat springs, 
large tubes for bicycle frames, etc. They are run 
on flanged pulleys, one of which is supported on 
a standard and the other, which is the driver, is 
sometimes mounted in place of a wheel on one of 
the polishing heads. 

Belt Strapping Machine. This belt strapping 
device shown in Figure 24 is simple in construc- 




Fig. 24. Belt Strapping Machine. 

tion aad easily operated. 
It is designed with a view 
of meeting the require- 
ments of the large variety 
of work which experience 
has shown can be econom- 
ically and rapidly pol- 
ished or roughed off by this method. The facility 
with which this machine can be operated makes 
it applicable for many small articles heretofore 
polished on regular wheels. 

This attachment can be used to great advantage 
by manufacturers of bicycles and bicycle parts, 



ELECTRO-PLATERS MATERIALS 



57 



brass cocks, and other plumbers' fittings, gas 
fixtures, grate and fender work, while for cutlery- 
it seems to be indispensable, as with no other 




Fig. 25. Burnishing Tools. 



device can the operator reach as well all sorts and 
conditions of metal surfaces that are inaccessible 
with the regular polishing wheels. 



58 THE ELECTRO-PLATERS HAND-BOOK 



Burnishing Tools. The work of burnishing is 
usually performed by means of steel tools, a com- 
plete set of which are illustrated in Figure 25. 

Hydrometers. These are glass instruments 
resembling thermometers in outward appearance, 
but having a large glass bulb near 
the bottom, as shown in Figure 
f 26. They are used for testing 

ill the specific gravity of liquids, or, 

in other words, to test their denr 
sity as compared with that of pure 
water. The liquid to be tested is 
placed in a narrow glass jar, Fig- 
ure 27, from the flask shown in 
the same figure, together with the 
hydrometer, or may be put in 
any other vessel. The instrument 
floats in the liquid to be tested, 
with its bulb below the surface 
and its stem standing above the 
surface. This stem is graded in 
degrees similar to that of a ther- 
mometer, and shows the depth of 
the bulb beneath the surface. In 
pure water the bulb sinks down to 
the degree mark, or to 1000 as 
marked on some scales, 1000 being 
taken to represent the density of 
water at a temperature of 60 
degrees Fahrenheit. As the den- 
sity of the water increases by the addition of 
salts or of liquids having a greater density than 



Fig. 26. 

Hydrometer. 



ELECTRO-PLATERS MATERIALS 



59 



water, the bulb is forced upwards, and the scale 
then registers so many degrees greater density 
than water. 

Two differently graduated hydrometers are in 
use in this country. These are: hydrometers 
graded to read 
direct the spe- 
cific gravity of 
liquids in com- 
parison with 
that of water, 
taking this as 
represented by 
1000, and hy- 
drometers grad- 
ed by a scale 
adopted by M. 
Baume, and 
calle d the 
Baume densi- 
meter. The dif- 
ference between the two gradings is shown in the 
following table. In some text-books and printed 
instructions on this art, reference is made to test- 
ing solutions by means of a hydrometer, and cer- 
tain figures are given to denote the required den- 
sity of the solution. These are fallacious unless 
direct reference is also given to the kind of hydrom- 
eter to be used. This will be seen on reference to 
the following table, wherein is shown at a glance 
the difference between the readings of Baume and 
the direct reading specific gravity hydrometers. 



< 




'T 



Fig. 27. 



Testing Jar and Flask for Use 
with Hydrometer. 



60 THE ELECTRO-PLATERS HAND-BOOK 

Table Showing Readings of Different 
Hydrometers. 



Baume 


Specific Gravity 


Baume 

37° 


Specific Gravity 


Baume 


Specific Gravity 


10° 


1.0000 


0.8395 


64° 


.7423 


11° 


0.9930 


38° 


.8346 


65° 


.7205 


12° 


.9861 


39° 


.8299 


66° 


.7168 


13° 


.9791 


40° 


.8251 


67° 


.7133 


14° 


.9722 


41° 


.8204 


68° 


.7097 


15° 


.9658 


42° 


.8157 


69° 


.7061 


16° 


.9594 


43° 


.8110 


70° 


.7025 


17° 


.9530 


44° 


.8063 


71° 


.6990 


18° 


.9466 


45° 


.8017 


72° 


.6956 


19° 


.9402 


46° 


.7971 


73° 


.6923 


20° 


.9339 


47° 


.7927 


74° 


.6889 


21° 


.9280 


48° 


.7883 


75° 


.6856 


22° 


.9222 


49° 


.7838 


76° 


.6823 


23° 


.9163 


50° 


.7794 


77° 


.6789 


24° 


.9105 


51° 


.7752 


78° 


.6756 


25° 


.9047 


52° 


.7711 


79° 


.6722 


26° 


.8989 


53° 


.7670 


80° 


.6689 


27° 


.8930 


54° 


.7628 


81° 


.6656 


28° 


.8872 


55° 


.7587 


82° 


.6619 


29° 


.8814 


56° 


.7546 


83° 


.6583 


30° 


.8755 


57° 


.7508 


84° 


.6547 


31° 


.8702 


58° 


.7470 


85° 


.6511 


32° 


.8650 


59° 


.7432 


86° 


.6481 


33° 


.8597 


60° 


.7394 


87° 


.6451 


34° 


.8544 


61° 


.7357 


88° 


.6422 


35° 


.8492 


62° 


.7319 


89° 


.6392 


36° 


.8443 


63° 


.7281 


90° 


.6363 



Thermometers. In electro-gilding operations a 
thermometer is needed to ascertain the right 
temperature of the gilding solution. This 
instrument must be wholly of glass, as any metal- 
work will dissolve in the hot gilding solution. 
The best for this purpose are those with a white 
enameled scale enclosed in a glass tube. The 
scale may be graded in degrees, Fahrenheit or 



ELECTRO-PLATERS MATERIALS 61 

Centigrade, as may be most convenient to the 
operator. If the scale is graded in Centigrade 
degrees, and it is desired to ascertain the value of 
a reading in degrees Fahrenheit, add 32 to the 
reading, multiply the product by 9, and divide it 
by o. If the reading is in degrees Fahrenheit, 
multiply the reading by 5, subtract 32 from the 
product, and divide it by 9 to convert the reading 
into Centigrade degrees. 

Rheostats, Use of. Rheostats are of the first 
importance in the plating room. Without them 
the varying degrees of current necessary for 
handling different solutions, or for manipulating 
baths of various sizes, cannot be obtained. 

A rheostat is necessary in the field of the 
dynamo where it will control the voltage along 
the entire line of connection, enabling an initial 
current strength to be maintained while the tank 
rheostats further reduce this current to the pro- 
portions required. 

The rheostat in the field, while it affects the 
voltage by setting a fixed resistance in the field 
of dynamo, does not affect the ampere capacity 
except in a minor degree. On the other hand 
the rheostat placed between the main line and 
the tank affects both the voltage and amperes, 
reducing the latter in the same proportion as the 
former is cut down. It is necessary, then, that 
the rheostat selected for the tank be of ampere 
carrying capacity sufficient to handle the current 
used in the tank. If the rheostat has not suffi- 
cient capacity to handle the ampere current a 



62 THE ELECTRO-PLATERS HAND-BOOK 



resistance is formed which prevents the proper 
amount of current from flowing into the tank. 

The action of a 
current of elec- 
tricity can be 
likened to the 
passage of water 
through a pipe, 
the force with 
which the water 
flows from the 
aperture repre- 
senting the volt- 
age, while the 




Fig. 28. Rheostat. 



quantity discharged may represent the ampere 
current. If a valve or stop-cock is placed in this 
pipe the action 
would be similar 
to that of the 
rheostat in an 
electric circuit. 
In arranging 
tanks it is neces- 
sary that con- 
ductors be of 
sufficient size to 
carry the great- 
est number of 
amperes the 
tankwillhandle. 
Different solutions require different amperes per 
square foot of work surface. 




Fig. 29. Voltmeter. 



ELECTRO-PLATERS MATERIALS 



63 



A plain rheostat is illustrated in Figure 28. 

Voltmeters. The voltmeter shown in Figure 29 
has a scale from to 6 volts and upwards. The 
scale is divided into 120 divisions, so that each 
division represent one- twentieth of a volt, and 
when used in connection with the switch boards 
will enable the plater to study carefully all the 
requirements that insure good results, and will 
give the means of accurately reproducing such 




Fig. 30. Combination Voltmeter and Rheostat. 



conditions as have been found by experience con- 
ducive to success. 

A combination of a voltmeter and a rheostat 
mounted on a slate base is illustrated in Figure 30. 

Ammeter. It is a fundamental law of elec- 
trolysis that a certain number of amperes passing 
through a plating solution will cause a definite 
weight of metal to be deposited. As, for instance, 
one ampere will deposit in one hour 1.106 
grammes of nickel, 4.15 grammes of silver. It is 
evident, therefore, that by means of an accurate 



64 THE ELECTRO-PLATERS HAND-BOOK 



ammeter, such as shown in Figure 31, the amount 
of metal actually deposited can easily be de- 
termined. 

Time Dial. To denote the time of taking the 
work out of the tanks, the dials illustrated in 
Figure 32 will be found to be very useful. They 

are made very 
strongly of 
bronze, oxidized 
and lacquered, 
w th nickel -plat- 
ed hands, and 
bright figures. 
They are eight 
inches in diame- 
ter, and are 
quite flat, and 
can be screwed 
up or suspended 
over or near 
tanks. 

Respirator. 
Figure 33 shows 
one of the latest 
forms of respira- 
tors. 

This is one of 
the best devices 
for protecting 
the throat and 
lungs from dust, 

Fig. 32. Time Dial. poisonous gases, 




Fig. 31. Ammetei 









1 f !l^^t^i^l>t^ 






iHWl 
mmmm 











ELECTRO-PLATERS MATERIALS 



65 



and all other impurities, in places where persons 
are exposed, and, many times, life endangered. 

In respiring, the air is inhaled through a thin, 
wet sponge or cotton, and, in expiring, passes 
out through an 
automatic valve 
in the side, so 
that breathing 
with the respir- 
ator is easy, 
allowing i t to 
be worn con- 
stantly, without 
the least incon- 
venience. They 
are manufac- 
tured of the 
best white rub- 
ber, and will 
last a lifetime. 
The sponge can 
be easily taken out, rinsed, and replaced in one 
minute. 

Steam Generators. Where no outside source or 
supply of steam is available, the steam generator 
shown in Figure 34 will be found a very useful 
adjunct to an electro -plating plant. 

. The generator has a ring below, a water front 
beneath the fire door, and water tubes surround- 
ing the fire and steam dome above. Cast iron 
shields fit in the spaces between and behind the 
tubes and extend around the heater from the top 




Fig. 33. Respirator. 



66 THE ELECTRO-PLATERS HAND-BOOK 



of the bottom ring and as high as the bottom 
of the fire door. These shields prevent the 

accumulation of 
ashes between 
the tubes. They 
also become hot 
and radiate their 
heat to parts of 
the tubes not ex- 
posed to the fire. 
There is an air 
space between 
them and the 
outer sheet steel 
jacket. In the 
smaller sizes a 
float and yalve 
to automatically 
regulate the wa- 
ter supply is 
placed inside the 
steam dome, while 
in the larger sizes 
this water-regulat- 
ing device is con- 
tained within an iron 
float box outside of 
the boiler, but con- 
nected to it by pipes, 
as shown. The safe- 
ty valve is set to 

Fig. 35. Rubber Gloves. blow 0&. at about 12 




Fig. 34. Steam Generator. 




ELECTRO-PLATERS MATERIALS 



67 



pounds' pressure and the float has buoyancy 
enough to shut off the water up to about 30 
pounds' pressure. In places, therefore, where 
there is a water works pressure of from 12 to 30 
pounds or so the boiler can be attached at the 
float valve to a pipe from the hydrant. Where 
pressure is above or below this or there is no 
water works a supply barrel or iron supply tank 
can be used. 

Rubber Gloves. Figure 35 shows two slyles of 

rubber gloves for platers' use when handling 

. chemicals, lye, 

acids, etc. 

Finger Cots. 
These finger 
cots, which are 
very necessary 
for the protec- 
tion of fingers 
against chemi- 
cals, and also 
for scratch- 
brush work, are 
shown in Fig- 
ure 36. 

Wooden 
Shoes. As wa- 
ter in abundance is found to be necessary for 
some plating and pickling operations, which keep 
the floors constantly wet, the shoes shown in 
Figures 36 are a very desirable article of wear 
for the plater. 




Fig. 36. Finger Cot and Wooden Shoe. 



68 THE ELECTRO-PLATERS HAND-BOOK 




Fig. 37. Rubber Apron. 



Rubber 
Aprons. Rub- 
ber aprons, 
which are very 
necessary dur- 
ing pickling or 
scouring opera- 



t i ons 



are 
Fig- 




Fig. 38. Felt Filter Baj 



shown in 
ure 37. 

Felt Bags. 

Felt filter bags 
for rapidly fil- 
tering solutions 
are shown in 
Figure 38. 

Glue Pot and 
Brush. In 
small plating 
shops where a 
steam supply 
is not avail- 
able, a glue pot 
and brush of 
the style illus- 
trated in Fig- 
ure 39 will be 
found very use- 
ful when it is 
desired to re- 
new the abrad- 
ing material on 



ELECTRO-PLATERS MATERIALS 



69 



the surface cf 
leather buffs. 

Rod and Wire 
Connectors . 

Connectors, as 
shown in Figure 
40, are almost 
an indispensable 
article of a plat- 
ing outfit to 
properly make 
the necessary 
connections be- 
tween the dyna- Fig. C9. Glue Pot and Brush. 

mo and plating Tats. Five different styles are 
illustrated in the drawing. 













P§ 




Pi 


/8I1H 


^y^Lw 






Fig 40. Rod and Wire Connectors. 



ELECTRO-DEPOSITION OF METALS 

Suitable Depositing Solutions. The first con- 
sideration should be given to a selection of the 
best depositing solution and one suited to the 
purpose in hand. Select a solution that will 
yield up its metal freely under the influences of the 
electric current, but one which will not deposit its 
metal on articles by simple immersion in the solu- 
tion. Choose a solution that will dissolve the 
anode freely, and thus maintain the solution in a 
constant working condition. These points having 
been observed, let the choice rest upon a solution 
made up in the most simple manner, out of the 
least number of ingredients. The solution should 
contain only the salts of the metal to be deposited, 
and these salts should break up at the cathode 
into deposited metal and its solvent, which should 
be retained in the solution. The best depositing 
solution for silver is one composed of the double 
cyanide of silver and potassium in distilled water. 
This solution will yield up its metal freely under 
the influence of a low voltage current of elec- 
tricity, and the double salt breaks up at the 
cathode into deposited silver and potassium 
cyanide. As the latter is a solvent of silver when 
this metal forms the positive electrode in a solu- 
tion of cyanide of potassium, the anode dissolves 
freely, and maintains the solution in working 

70 



ELECTRO-DEPOSITION OF METALS 71 

order. That is to say, it furnishes to the solu- 
tion an equivalent of silver for each equivalent 
withdrawn. All the double cyanide salts are of 
general utility, forming excellent depositing solu- 
tions of gold, silver, platinum, copper, zinc, and 
mercury. 

Metals Easily Deposited. Gold may be de- 
posited from its solution of the double cyanide of 
gold and potassium in good condition under the 
influence of a very feeble current of electricity. 
Copper is also easily deposited from its solution 
of copper sulphate. This solution will deposit 
copper on zinc, iron, and steel, by simply im- 
mersing these metals in the solution, but the cop- 
per so deposited can be easily rubbed off again, as 
it is only a mere film obtained by chemical action 
on the surface of the immersed metal. The 
voltage needed to decompose a solution of copper 
sulphate may be as low as half a volt, and in most 
cases need not exceed one volt. Higher voltages 
than these are necessary to overcome resistances 
met with in actual practice and to effect rapid 
depositions of the metal. To deposit copper from 
its alkaline solutions, a current of higher voltage 
is required, varying from 5 to 10 volts according 
to the resistance of the work in the circuit. Sil- 
ver requires a current of higher voltage to deposit 
it from its solution of the double cyanide of silver 
and potassium, than that required for gold. 

Metals of Low Cost. The least costly metals 
are not, as a general rule, the most easy to deposit 
in a good condition. Iron may be placed first, as 



72 THE ELECTRO-PLATERS HAND-BOOK 

being of least cost, but it cannot be easily de- 
posited in good condition. Zinc is also a cheap 
metal, but there are difficulties attending its 
deposition. Tin may be easily deposited, but the 
depositing solution needs careful attention to 
keep it in working order. Lead offers little of 
practical interest to the plater. The same may 
be said of bismuth and antimony. Copper is a 
useful metal, of moderately low cost, and one 
easily deposited in good condition. 

Nickel, as compared with copper, is a costly 
metal, but it is also a very useful metal. Cobalt, 
the sister metal of nickel, has not come into gen- 
eral use, but it may be classed with that metal. 
Silver is the plater's metal, and a general favorite 
with amateur platers, as it is easily deposited. 

Metals Not Easily Deposited. Although such 
metals as gold, copper, and silver may be easily 
deposited in good condition from suitable solu- 
tions when employing an electric current of low 
voltage, this only touches the question of com- 
paratively easy deposition and the rapidity of the 
process under suitable conditions. The condition 
of the deposited metal is greatly affected by the 
tenuity or the density of the solution, and the 
strength of current as well as its electromotive 
force or voltage. Some metallic salts need a 
higher voltage to decompose them than others, 
but the main consideration must be directed to 
current strength rather than to voltage, since 
the quantity of metal deposited from a solution 
in a good condition in a given time will greatly 



ELECTRO-DEPOSITION OF METALS 



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74 THE ELECTRO-PLATERS HAND-BOOK 

depend upon the number of amperes of current 
we can get through the solution. The salts of 
nickel, zinc, tin, and iron appear to need a cur- 
rent of greater strength to decompose them than 
those of gold, silver, and copper. 

Rate of Deposit of Metal. Each metal has its 
own peculiar qualities which govern the rate at 
which it can be deposited in a good condition. 
This condition has been named a reguline state, 
that is, a state nearly like that of the metal when 
melted and cast in a mould. Electro-deposited 
metal, however, is generally so porous, even in its 
best condition, as to be rarely air-tight and water- 
tight. The quality of a deposit is governed by 
the quality of the solution from which it was 
obtained, the temperature of the solution, and 
the quantity of electric current passing through 
the article to be coated, in a stated time. This 
last is called the density of the current, and it 
determines the quantity of metal which can be 
deposited in a given time. The following list 
shows the quantity of metal which can be de- 
posited with a current density of one ampere on 
one-tenth of a square foot of surface in one hour. 

Aluminium, 52.4977 grains. 



Silver, 


52.1142 


Zinc, 


18.7240 


Copper, 


18.1638 


.Gold, 


37.7290 


Nickel, 


16.9030 



CLEANING THE WORK 

The term cleanliness, when applied to metal 
surfaces about to receive a coat of electro-de- 
posited metal, means absolute freedom from the 
least trace of dust, grease, or other animal mat- 
ter, rust, corrosion, or any other form of oxidized 
metal. As an example, a surface made clean by 
any mechanical means alone will not serve the 
purpose, because loose metal dust and minute 
particles of the polishing material may be left on 
the surface, or the cleaning material may be oily 
or greasy, and the particles of dirt thus left on 
would prevent perfect adhesion of the deposited 
metal. If a perfectly clean surface bo handled 
with the naked hand, the deposited coat will 
strip off the spots touched with the hand. The 
surfaces to be plated must therefore be made 
clean by mechanical means, and then made 
chemically clean by suitable solutions of acids or 
of alkalies. Each metal requires a slightly differ- 
ent treatment to that of others. 

Cleaning Cast Iron. Iron castings may be 
coated with copper or with brass in an alkaline 
bath, or with nickel or zinc, but are rarely coated 
with silver or with gold. The method of clean- 
ing is the same for each process. The casting 
must be first freed from the hard black crust of 
burnt sand on its surface, and particles of sand 

75 



76 THE ELECTRO-PLATERS HAND-BOOK 

from its pores. To do this, immerse the casting 
in a pickle composed of six fluid ounces of sul- 
phuric acid to each gallon of water, and let it 
soak for half an hour. If, at the end of this 
time, the black crust has become sufficiently 
loose to be rubbed off with the tip of a finger, 
the operation of pickling is complete. If there 
are obstinate scales, re-immerse it in the pickle 
for a short time, then try the hard, spots again. 
If they are still obstinate, pour a little muriatic 
acid on them and put the casting again in the 
pickle. When the black scale is all loosened, 
rinse the casting in water and take it to the 
scouring tray, where it must be scoured with wet 
silver sand and a hard brush until a clean, bright 
surface has been obtained. If there are any 
sand-holes, these must be cleaned out with a 
sharp steel point, and the clean, bright casting 
rinsed at once in clean water, then transferred 
without loss of time to a cold potash solution. 
In this it may remain for a short time whilst 
getting the bath ready, when it must be again 
rinsed in clean water, and transferred at once to the 
bath of copper, nickel, brass, tin, or zinc. If the 
casting is large, a number of stout slinging wires 
must be employed, as cast iron itself is an inferior 
conductor of electricity. If the casting is greasy, 
or has been used where oil could get on it, the 
costing must be put in a hot potash dip, scoured, 
and rinsed before placing in the acid pickle. If 
it is rusty, the rust spots should be smeared with 
muriatic acid before being placed in the pickle. 



CLEANING THE WORK 77 

Cleaning Wrought Iron or Steel. Wrought iron 
should be treated in a similar manner to cast iron, 
the pickle being the same for both, but it will 
not be necessary to leave the articles so long in 
the pickle before scouring them. As a high 
polish may be desired on wrought iron and steel 
ai tides, this is given to them on the polishing 
lathe by means of emery wheels, and bobs charged 
with sand, lime, emery, rough cut tripoli, and 
other abrading substances, to first grind down all 
roughness, then finish with crocus powder on a 
leather mop, or with the crocus powder on a cir- 
cular bristle brush. After being thus brought to 
a high state of polish they should be passed 
through the potash dip to free them from the 
grease contracted in polishing, rinsed in water, 
and brushed with a soft brush free from grease, 
then transferred at once to the plating vat. 
Should there be any delay in finishing the pol- 
ished steel, or should the article be large, its sur- 
face will be sure to contract a slight film of rust, 
and this must be removed by clipping each article 
for a few moments in a pickle composed of eight 
fluid ounces of muriatic acid in each gallon of 
water, then rinsing in water and transferring at 
once to the plating bath. Celerity in finishing 
wrought iron and steel is necessary, because of 
the tendency of these metals to rust when wet 
and exposed to the air. The slightest film of 
rust, not to be detected by the eye, will be suffi- 
cient to cause a loose deposit which will strip 
whilst being finished or burnished. 



78 THE ELECTRO-PLATERS HAND-BOOK 

Cleaning Copper, Brass, and German Silver. 

As brass and German silver are alloys of copper 
with zinc and nickel, they may be conveniently 
classed together for preparatory treatment, this 
being the same for all of them. There are several 
other alloys of copper with zinc, nickel, tin, 
aluminium, and iron, but to the plater they are 
all brass, and are to be treated in a similar man- 
ner in preparing them for plating. It must be 
distinctly understood beforehand that defects in 
the surfaces of metals cannot be covered up by 
depositing upon them a coat of another metal. 
If the surface of the article is scored with 
scratches, or pitted with corrosion, the scratches 
and pits, however small, will appear on the 
plated surface, and cannot afterwards be effectu- 
ally removed by subsequent polishing and burnish- 
ing. Even when the surface has been highly 
polished, if it should be accidentally marred by a 
stain, the dull, irregular spot will appear on the 
plated surface and mar its appearance. This fact 
points to the necessity of care being taken in 
removing all scratches and other roughness from 
the surface by a series of polishings, beginning 
with rough cutting materials on bobs and buffs 
made of bull-neck, walrus, and leather, felt, etc., 
and finishing off with the finer abrading materials 
on calico and swansdown mops. In large estab- 
lishments this work is done in the polishing room 
by men who devote their whole time to this 
branch of the business, and the polished articles 
are handed into the plating room on shallow 



CLEANING THE WORK 79 

wooden trays. As they leave the hands of the 
polisher their surfaces have a bright, lustrous 
appearance, and it would appear to the uniniti- 
ated that it would be only necessary to wire the 
goods and hang them at once in the plating vat, 
so clean and bright do they appear. As a fact, 
the smooth, bright surface left by the polisher is 
covered by a slight film of grease left from the 
polishing materials, and this must be removed by 
soaking the goods in a hot potash dip. They 
must therefore be connected to lengths of wire 
and suspended in the hot potash solution until 
wanted at the scouring trough. After the film 
of grease has been removed in the potash dip, the 
articles are taken one at a time to the scouring 
trough and laid on a transverse shelf of wood, 
whilst briskly brushed with hogs' bristle brushes 
dipped in finely-powdered pumice stone, or with 
a mixture of equal parts pumice and rotten stone. 
This is done to clear off the last remaining trace 
of animal matter, and also to impart a slight uni- 
form roughness to the surface, such being neces- 
sary to insure perfect adhesion of the deposited 
coat of metal. To insure this, it is not necessary 
to scour the surface hard, but to merely brush it 
briskly to and fro with a wet brush charged with 
the scouring powder, care being taken to keep 
the brush well charged with the powder. The 
brush to be used for this purpose must be free 
from grease, but should the presence of grease or 
oil be suspected, it will be well to take the pre- 
caution of dipping the hairs for an instant in the 



80 THE ELECTRO-PLATERS HAND-BOOK 

potash solution and rinsing the brush in water 
before using it. The scouring trough should be 
divided into two parts, one division being used for 
scouring and the other containing water for rins- 
ing the scoured articles. The powdered pumice 
is held in a box fixed to the inside edge of the 
scouring division, furthest from the workman, 
who first dips his brush in the water and shakes 
out the surplus, then dips it in the box of powder, 
some of which adheres to the wet hair. This 
process is repeated as the powder wears off, and, 
when the article is properly scoured, it is rinsed 
in the water contained in the rinsing division, 
wired with the necessary slinging wires, dipped 
in the final dipping solution, again rinsed in clean 
water and suspended at once in the plating 
solution. 

While German silver, brass, and some other 
alloys of copper are being scoured, they contract 
a slight film of oxide. If the cleaned articles are 
to be nickel-plated, this film is removed by dip- 
ping in a solution of cyanide of potassium in 
water, called a cyanide dip, and this is the final 
dip before placing the goods in the plating vat. 
If the goods are to be silver-plated, they should 
receive a final dip in a dilute solution of nitrate 
of mercury, which coats the surface with a thin 
film of mercury. This process, named quicken- 
ing, is adopted to remove the film of oxide already 
noticed, and to replace it with a film of clean 
metal to which the silver can closely adhere. It 
is sometimes used in preparing articles to be 



CLEANING THE WORK 81 

gilded, but quickening is not always necessary to 
perfect adherence of silver or of gold. If the 
gilding or plating solutions are properly pre- 
pared, and the scouring operations conducted with 
sufficient celerity and care, a perfect adherence 
of the gold or silver coat can be secured by swill- 
ing the article in a cyanide dip, as for nickel- 
plating, or by merely moving it to and fro in the 
plating bath for a few moments before connecting 
the slinging wires to the cathode rod. 

Cleaning Old Articles. Much of the plater's 
time in jobbing shops will be taken up in plating 
old articles, or in re -plating those that have 
formerly been coated with tin, zinc, nickel, silver, 
brass, or gold. The first consideration should be 
paid to the nature of the old plated coat, with a 
view to adopting the proper means for its complete 
removal, since successful re-plating of articles 
coated with patches of metal cannot be done. 
As old articles are generally more or less dis- 
colored by tarnish and dirt, this coat must be 
first removed by boiling in potash solution and 
brushing with the scratch-brush. Gold may be 
distinguished from brass by dropping on the coat 
from the tip of a glass rod a single drop of 
nitric acid. This acid will immediately dissolve 
the brass and cause a green spot, but on gold it 
will not have any effect. Silver may be distin- 
guished from nickel or from German silver by 
dropping on the coat a mixture of Smarts nitric 
acid and 1 part chromic acid, to which has been 
added 2 parts of water, or 2 parts strong bi- 



82 THE ELECTRO-PLATERS HAND-BOOK 

chromate of potash solution instead of chromic 
acid. If silver is present, it will be indicated by 
a blood-red spot where the mixture attacks the 
metal, while a greenish spot will reveal the pres- 
ence of Qerman silver or of nickel. Tin and zinc 
will freely dissolve in a mixture of muriatic acid 
and water, but this will have no effect on silver 
and very little effect on nickel. When the outer 
coat of grease, dirt or plated metal has been re- 
moved, the surface will be seen to be pitted, 
scratched and otherwise worn. These marks 
must be removed on the polishing lathe or by 
hand if the re-plated article is to have a finished 
appearance, unless in so doing the metal is worn 
too thin to be of any use. When the surface is 
thus polished, it must be further treated as new 
work to be plated. It sometimes happens that 
old goods are made up in pieces put together with 
soft solder. These soldered joints will clearly 
appear after the dirt and outer coats have been 
removed, and are likely to cause trouble if not 
discovered and properly treated before placing 
the goods in the plating vat. Soldered joints 
must be coated with copper in the following man- 
ner after the article has been scoured. A small 
glue brush or paint brush must first have some 
fine iron wires twined among its hairs, which 
must then be dipped in a strong solution of sul- 
phate of copper and drawn along the soldered 
seam. This will cause a thin film of copper to 
be deposited on the solder, and this film will 
readily take the mercury from the quickening solu- 



CLEANING THE WORK 83 

tion. If there are large patches of solder or lead 
mounts on the article, it will be best to coat the 
whole article with copper or with brass in an 
alkaline coppering or brassing solution before 
attempting to plate it with silver, gold, or nickel. 
If old cruet-stands are made up of two or more 
different kinds of metals or their alloys soldered 
together, these must be unsoldered and the differ- 
ent parts treated apart, or the whole must be 
coated with copper in an alkaline copper bath 
before plating. It sometimes happens that 
articles are made up of tinned iron bottoms, cast 
pewter legs and sides soldered together, German 
silver or brass wires and steps, and pewter knob 
or loop at the top. These parts may be detected 
by scraping some obscure spot with an old knife 
or a file. As such dissimilar metals will not plate 
together in the bath at the same time, because 
they form galvanic pairs in the solution, we 
must either separate them by unsoldering, and 
plate them separately, soldering them together 
again afterwards, or give the whole a coat 
of copper under a vigorous current, then 
quicken with mercury and re-plate without loss 
of time. 

Cleaning Work by Hand. The use of ma- 
chinery for polishing metals has, to a certain 
extent, superseded the old practice of preparing 
and finishing the articles by hand. As a large 
quantity of good work has been frequently done 
by hand in the past, the same quality of work 
may still be turned out in small shops, where all 



84 THE ELECTRO-PLATERS HAND-BOOK 

the scouring, polishing and brushing must be 
done by hand. The first thing to be done is to 
remove all dirt and corrosion. This is effected 
by means of the acid and other dips, combined 
with alternate brushings with coarse bristle and 
wire brushes in the scouring trough. Next is the 
removal of all corrosion pits, scratches and other 
damages to the surface. The first part of the 
process is done with lumps of pumice stone 
previously faced by rubbing on a flat stone. 
With these prepared lumps dipped in water, all 
the corroded and scratched parts of the surface 
are gone oyer, grinding them down until they are 
almost obliterated, then the entire surface is gone 
over in a similar manner to produce a uniform 
effect. This done, well rinse the article and dry 
it. When dry, go over all the surface with a 
piece of fine emery cloth placed over a bung, and 
rub out the scratches made by the stoning proc- 
ess. Scour off all traces of emery with a soft hair 
brush in water, well rinse the surface and go all 
over it with rotten stone to rnb out all the 
scratches made by the emery. The stone must 
be frequently dipped in water and rubbed in one 
direction, going over nil the surface until it 
appears quite smooth. When this has been ac- 
complished, the surface may be finished with a 
piece of buff leather smeared with fine cut crocus, 
fine cut tripoli, or rotten stone and oil, the leather 
being glued to a stick or held over a bung. The 
polished surface may now be scoured and pre- 
pared for plating. 



CLEANING THE WORK 85 

Polishing Jewelry. Such articles as studs, 
sleeve links, solitaires, buttons, earrings, finger 
rings and small brooches become tedious to polish 
when a large number of them have to be done by 
hand at one time. In factories where a large 
number of such things have to be polished, they 
are all put together in a rumble, that is, a barrel 
revolved by machinery, and polished by friction 
against each other. This may be imitated by 
hand, using a canvas sack instead of a barrel. 
The small goods are placed in a long canvas bag 
with some dry sawdust, and well shaken by two 
persons, one at each end, or one end may be tied 
to a post and the other shaken up and down 
until the small goods are polished. 



DIPS AND DIPPING 

When articles are in a good state of polish as 
regards the mere smoothness of the surface, but 
are coated with a film of oxidized metal, that is, 
tarnished, and are also free from animal matter, 
such as grease, the required condition of surface 
for plating may be imparted by dipping them in 
an acid solution and then swilling them in an 
abundance of clean water. This process is called 
dipping, and the acid solutions are known as dips. 
Copper, brass, German silver, and all copper 
alloys, may be dipped in commercial nitric acid, 
or in a mixture composed of nitric acid, 2 pints — 
sulphuric acid, 4 pints — water, 1 gallon. If this 
does not work well on bronze, German silver, and 
yellow brass, add a little hydrochloric acid, say 
one fluid ounce at a time, until the desired effect 
has been obtained. 

Potash and Cyanide Dips. To free the surfaces 
of metal from grease left by the polishing proc- 
esses, it is necessary to steep the articles in a hot 
potash dip made by dissolving half a pound of 
caustic potash or Babbit's potash in each gallon 
of water employed. This solution should be kept 
in a wrought-iron tank or pot, with means pro- 
vided for keeping it hot. As its solvent power is 
impaired quickly by contact with air, it should 
be covered np when not in use, and as its caustic 

86 



DIPS AND DIPPING 87 

properties are neutralized by the grease dissolved 
off the articles, the solution must be kept in 
working order by frequent renewals. Care must 
be taken in handling the material and its solu- 
tions, as it has a powerful caustic action on the 
skin. Cyanide dips are employed to dissolve 
slight traces of oxide from the surfaces of goods 
prepared for nickel-plating. The dip is prepared 
by dissolving half a pound of commercial cyanide 
of potassium in each gallon of water contained in 
a stoneware vessel. This dip is used cold. 

Iron Pickle. A pickle for iron is made by mix- 
ing in a stone jar or tank, according to quantity, 
the following solution: Sulphuric acid 1 part, 
water 15 parts. Muriatic acid may be substituted 
for the sulphuric if desired. 

Bright Dip for Iron. A dip which leaves the 
surface of the metal bright is made by mixing 
slowly in the following order: Water 240 parts, 
sulphuric acid 28 parts, zinc 2 parts, nitric acid 
12 parts. 

Copper, Brass and Bronze Pickle. The castings 
should be pickled in dilute muriatic acid to remove 
the scale, and then cleaned and brightened by 
dipping in a solution made up as follows : Sul- 
phuric acid 50 parts, nitric acid 100 parts, com- 
mon salt 1 part, lamp black 1 part. 

Bright Dip for Copper or Brass. Copper or 
brass work that is not to be buffed or polished 
should be first dipped in a pickle of nitric acid 
200 parts, common salt 1 part, lamp black 2 
parts. 



88 THE ELECTRO-PLATERS HAND-BOOK 

After pickling until clean, thoy should be 
thoroughly rinsed in boiling water, allowed to dry 
for a moment and then plunged into the following 
solution: Mtric acid 75 parts, sulphuric acid 100 
parts, common salt 1 part. 

Cyanide Dip for Brass. Cyanide of potassium 
in ten times its weight of water should be used as 
a preliminary dip when plating articles that would 
otherwise have the polish injured by the acid 
dips. The work must be allowed to remain 
longer in this than in the acid solution. 

Pickle for German Silver. German silver may 
be cleaned in the bright dip for copper or brass, 
or in a preliminary pickle of dilute nitric acid and 
water, 1 part of nitric acid to 12 parts of water, 
followed by a dip in equal parts of sulphuric and 
nitric acids to 24 parts of water, and then rinsing 
in boiling water and drying in sawdust. 



STRIPPING 

This term is employed to denote not only an 
accidental loosening of the deposited metal under 
the scratch brush or the burnisher, but also a pur- 
posed loosening of a deposit by means of acid 
solutions. Silver is stripped from old plated 
work on copper and its alloys, before they can be 
re-plated, by immersing the plated article in hot 
and strong sulphuric acid, and adding from time 
to time a few crystals of saltpeter. The acid 
must be made hot, the articles to be stripped 
must be quite dry before immersing them in the 
acid, and must be moved about while adding the 
saltpeter. If this is done as directed, the whole 
coat of silver may be loosened without serious 
damage to the metal beneath. The same opera- 
tion may be performed in a cold mixture, com- 
posed of 1 part strong nitric acid added to 10 
parts of sulphuric acid in a stoneware vessel. 
The goods to be stripped in these acids should be 
first attached to stout wires, as they must be fre- 
quently moved about in the solution, and taken 
out to be examined from time to time, to prevent 
overdoing the process and injuring the metal 
beneath the coat. When all the silver has been 
stripped off, the article must be at once rinsed 
in clean water to free it from acid; but should it 
be necessary to re-immerse the article, it must 

89 



90 THE ELECTRO-PLATERS HAND-BOOK 

be first dried, since the presence of water in the 
acid will canse it to attack the metal beneath the 
coat of silver. When the plated article is made 
of iron, steel, zinc, pewter, lead, or white metal, 
it mnst not be immersed in the stripping acid, 
but should be desilvered in a solution of cyanide 
of potassium by means of a current from a bat- 
tery or a dynamo. An old disused plating solu- 
tion will do very well for this purpose if it has 
plenty of free cyanide. Immerse the article to 
be stripped, and connect it as an anode to the 
positive pole of the battery or dynamo, and sus- 
pend a plate of carbon or a strip of platinum foil 
in the solution as a cathode. Then pass a strong 
current until all the deposited coat of silver has 
been dissolved. Gold may be removed from 
gilded articles by a similar method in an old gild- 
ing solution. The gilt insides of cups and mugs 
can be removed by filling them with the cyanide 
solution, connecting them to the positive pole of 
the battery and passing a strong current from 
them to platinum cathodes suspended in the solu- 
tion without touching the sides of the vessels. 
Gold may also be stripped from base metals by 
immersing them in hot nitric acid and adding 
some common salt as required. This operation is 
similar to the acid process for stripping silver, 
and needs equal care. Nickel is stripped from 
nickel-plated articles in a mixture composed of 1 
pint of water, 1 pint of strong nitric acid, and 4 
pints of strong sulphuric acid. The water must 
be first placed in a lead-lined vessel, or in one of 



STRIPPING 91 

enameled iron, and the sulphuric acid added 
gradually and carefully, as the addition of this 
acid to water raises its temperature to a boiling 
point. When the sulphuric acid has been mixed 
with the water, the mixture must be poured into a 
stoneware dipping pan and the nitric acid added. 
These precautions are necessary, because the 
mixture of the two acids and water will dissolve 
lead and enamel, but will not pierce acid-proof 
stoneware, whilst this in turn will not stand sud- 
den expansion caused by the heat generated in 
mixing the sulphuric acid with water. Whenever 
this acid is to be mixed with water, the acid must 
be poured slowly into the water, instead of mix- 
ing them by pouring water into acid. All opera- 
tions in stripping by acids must be performed in 
the open air, or under conditions similar to those 
laid down for dipping processes. The process 
must be closely watched throughout, and the 
article removed from the stripping solution imme- 
diately its coat of metal has been stripped off. 
The time taken up in this operation may be only 
a few minutes if the coat is thin, or it may ex- 
tend to half an hour, or even more when thick 
coats have to be stripped. 

Cleaning Zinc. Some highly artistic and orna- 
mental articles in cast zinc have the appearance 
of solid silver and solid gold imparted to them by 
electro-plating. Zinc goods of all kinds should 
be first immersed for a few minutes in a hot potash 
solution to free the surface from any trace of 
grease, then well rinsed and immersed in a 



92 THE ELECTRO-PLATERS HAND-BOOK 

pickle composed of sixteen fluid ounces of sul- 
phuric acid to each gallon of water for a few min- 
utes, then rinsed to free the surface from acid 
and passed on to the scouring trough. Here they 
must be dealt with at once and scoured with a 
stiff brush charged with wet silver sand until the 
surface has been made uniformly bright, then 
rinsed in water and transferred to a brassing or 
alkaline copper bath rich in metal. The current 
should be strong enough to coat the article with 
brass or with copper in a few seconds, to prevent 
the surface from being blackened by the solu- 
tion. When a film of copper or of brass has gone 
all over the surface, the anode should be raised 
and deposition allowed to go on more slowly. . If 
the article has been made up in pieces put 
together with soft solder, or if the zinc casting 
has been doctored with solder, the soldered seams 
or patches may not at first receive a deposit of 
copper or of brass, but will appear black after the 
rest of the surface has been coated. In this case 
the article must be taken out, the black spots 
well scratch-brushed, rinsed with water, and 
placed again in the brassing or coppering bath with 
the defective spots close to the anode. By care- 
fully moving the goods so as to bring the anode 
close to the defective spots in turn, they may be 
soon coated with metal. After the zinc has been 
thus coated with brass or with copper, it may be 
made to receive an adherent coat of gold or silver, 
and should be transferred directly from the brass- 
ing or coppering solutions to the gilding or plat- 



STRIPPING 03 

ing solutions. If the finished gilded surface is to 
be bright, the article should go direct from the 
brassing to the gilding solution, but if some parts 
are to appear dead and others bright, the brassed 
zinc must be placed in a silvering solution until 
it gets a dead -white coat of silver, then rinsed, 
and the intended bright parts scratch-brushed 
and burnished before placing in the gilding bath. 

Cleaning White Metal and Pewter. These 
alloys of lead and tin, as well as the metals of 
which they are composed, require a special course 
of treatment to fit them for receiving an adherent 
coat of silver or of gold 1 . The oxides of these 
metals and their alloys are soluble in hot caustic 
alkali solution. It is only necessary to immerse 
them in a hot solution of caustic potash to 
loosen any dirt or corrosion, brush the surface 
clean and bright, rinse again in a caustic potash 
solution, and transfer at once to the silver-plating 
vat. If they are to be coated with gold or with 
nickel, they should be transferred to a hot brass- 
ing or coppering bath and receive a coat of brass 
or of copper before placing them in the gold or 
the nickel bath. 

Cleaning Silver and Gold. Tarnish on silver 
may be loosened by immersing the article in a hot 
solution of cyanide of potassium. Discolored 
gold may be cleaned in a similar manner. Strong 
warm carbonate of ammonia solution will also 
loosen the tarnish on silver. After being thus 
loosened, the tarnish must be removed by brush- 
ing and scouring, or by means of a scratch brush. 



94 THE ELECTRO-PLATERS HAND-BOOK 

A special form of brush is used to prepare the 
insides of silver vessels about to be electro-gilfc. 
Filigree work, and similar delicately formed 
articles in gold and silver, should be first heated 
on a jeweler's warming pan before plunging them 
in the hot cyanide solution, as this class of goods 
cannot be cleaned by brushing or scouring. The 
articles to be cleaned should be covered with 
slices of lemon in a vessel for several hours. 
They are then rinsed in water, boiled in soap- 
suds, again rinsed, and finally dried on a hot- 
water bath. Silver may also be cleaned by boil- 
ing in potato water. 

Clearing off Corrosion and Bust. Corroded 
copper, brass, German silver, and similar alloys, 
must be first immersed in a pickle composed of 
sulphuric acid 3 pints, nitric acid If pints, water 
4 pints. This will loosen and dissolve the cor- 
rosion. Corroded zinc should be immersed in a 
pickle composed of sulphuric acid 1 fluid ounce, 
hydrochloric acid 2 fluid ounces, water 1 gallon. 
Rusty iron or steel should be first pickled in a 
solution composed of sulphuric acid 6 fluid 
ounces, hydrochloric acid 1 fluid ounce, water 1 
gallon. When the rust has been removed, im- 
merse the iron or steel in a pickle composed of 
sulphuric acid 1 pint, added to 1 gallon of water 
in which one-quarter of a pound of zinc sulphate 
has been previously dissolved. Dirty lead, 
pewter, white metal, and tin, may be cleaned in 
a hot solution of caustic potash or caustic soda. 



ELECTRO-PLATING WITH NICKEL 

Nickel is deposited from its solutions at the 
rate of .004641 grains per ampere second, or at 
the rate of 16.756 grains per ampere hour on one- 
tenth of a square foot of surface. 

The thickness of a nickel deposit may be ascer- 
tained by noting the strength of current em- 
ployed and the exact surface of metal coated with 
nickel in a given time, then, knowing that 1 
square foot of nickel 1,000th of an inch in thick- 
ness weighs 319.752 grains, the thickness of the 
whole deposit, together with its weight, may be 
found by calculation. 

Voltage Required to Deposit Nickel. To break 
up the nickel salt in solution and deposit the 
metal in good condition on an article when first 
placed in the bath will require an electromotive 
force of from 5 to 6 volts, or that furnished by 
from 3 to 4 battery cells in series. If a plating 
dynamo does not give the necessary voltage to 
deposit nickel in good condition, it may be made 
to do so by driving it at a higher rate of speed. 
As a rule, there should be a flow of hydrogen gas 
observable from the article being nickeled, but 
this may be excessive. Therefore the voltage and 
strength of the current must be regulated until 
the best results have been obtained by experience. 
When the articles have been covered with a thin 

95 



96 THE ELECTRO-PLATERS HAND-BOOK 

film of this metal, the intensity of the current 
may be reduced, and deposition allowed to go on 
more slowly, to insure a tough deposit. The 
intensity of one cell may then be found sufficient 
for the purpose. 

Finishing Nickel Plating. Mckel deposits 
differ from those of silver in appearance and 
hardness, and must receive different treatment. 
Deposition must go on from the start to the fin- 
ish without interruption. We may not remove 
the article to see how the deposit will stand 
brushing, as in the case of silver; if this is done 
the next layer will be likely to strip from the 
first. The deposit of nickel may not be white or 
brilliant, but of a dull yellowish appearance when 
it leaves the vat. It must then be well rinsed in 
hot water and dried, then passed over to the fin- 
isher, who changes the dull yellow surface to the 
brilliant polish desired by brushing the deposit 
with mops and dollies charged with lime. This 
is best done on the polishing lathe, with circular 
mops and dollies made of felt, calico and swans- 
down, the final finishing polish being imparted 
with a very soft clean mop. The articles should 
then be brushed with a soft brush to remove all 
traces of lime left in crevices on the article, and 
wiped with chamois leather. Nickel deposits 
should not be scratch -brushed with brass scratch- 
brushes, because the brass will wear off the 
brushes, and become embedded in the harder 
nickel deposit, causing it to have a brassy appear- 
ance. If there should be any faulty spot from 



ELECTRO-PLATING WITH NICKEL 97 

which the coat strips while being finished, it may 
be remedied by applying a small strip of nickel 
anode bound up in a rag pad dipped in the nickel 
solution and connected by a wire with the battery 
or dynamo. Rest this pad on the well-cleaned 
bare spot, connect a wire from the negative pcle 
of the battery to the article, and pass a current 
from the pad to the article until the bare spot 
has been coatsd with nickel. Experienced plat- 
ers and finishers can so work this between them 
as to successfully patch up a spot and render it 
indistinguishable from the rest of the article, 
thus avoiding the necessity of having the work 
re-nickeled. This will do for small faults dis- 
covered in finishing, but when the coat strips off 
in large patches, or in several such patches, the 
whole coat should be stripped and the whole work 
of preparation gone over again as at the first. 

Care of Nickel Baths. Nickel baths should be 
as carefully guarded against contamination with 
dirt and impurities as those of silver. The 
anodes should be always left in the bath, but the 
connecting wires and the sides of the vat should 
be frequently cleansed from the nickel salts which 
cre.p out of the solution and crystallize upon 
them. When the solution gets contaminated 
with dirt, and this interferes with the cleanly 
working of the bath, it should be filtered through 
a calico filter. If the metal is withdrawn from 
the bath faster than its equivalent is dissolved 
from the anodes, the solution will become acid, 
and this acidity must be neutralized by adding 



98 THE ELECTRO-PLATERS HAND-BOOK 

liquid ammonia to the solution in small quantities 
at a time, while stirring, until it ceases to redden 
blue litmus paper. When the solution becomes 
too dirty to be used, or is otherwise spoiled, all 
the nickel may be recovered as a double salt of 
nickel by adding to it a saturated solution of 
ammonium sulphate until the double salt falls 
and the solution loses its green color. The crys- 
tals thus obtained may be dissolved in hot water, 
the solution filtered and purified by crystalliza- 
tion to form a new bath. 

If an old nickel solution fails to give a satisfac- 
tory deposit of metal, it may be improved by add- 
ing some common salt to the extent of from 1 to 
10 per cent of the nickel salt in solution. The 
addition of common salt increases the conduc- 
tivity of the solution, and gives a whiter deposit 
of nickel than that obtained from an impure solu- 
tion of double sulphate of nickel and ammonia. 

If a nickel solution becomes too alkaline, as 
shown by a yellow deposit, and its power to turn 
red litmus paper to blue, add sulphuric acid until 
it shows a slightly acid reaction. 

Nickel-plating Cycle Fittings. It is not neces- 
sary to coat cycle fittings with copper previous to 
coating them with nickel, but it is advisable to 
do so for several reasons. A coat of copper will 
adhere firmly to iron and steel and other metals 
if these are properly prepared, and will show 
defects in the preparation, readily, by not coat- 
ing the defective parts. These defects can be at 
once remedied without loss of time and nickel. 



ELECTRO-PLATIXG WITH NICKEL 99 

Xickel will also firmly adhere to copper, and the 
two together form a better protecting coat than 
that of nickel alone. Some platers not only 
deposit a good coat of copper on high class work, 
bat also polish this, and re-copper the surface 
before depositing nickel on the fittings. Which- 
ever method is adopted, it must be borne in mind 
that success not only depends on a good coat ef 
copper, but also on absolute cleanliness in the 
preparation, for only a touch with the bare hand 
on the prepared article will cause the nickel to 
strip from the spot whilst being polished. In a 
good coppering solution a sufficiently durable coat 
of copper should be obtained in from fifteen to 
twenty minutes. 

Re-plating Old Cycle Fittings. Much of the 
work of a cycle plater consists of old fittings sent 
to be re-plated. All of the old nickel must be 
stripped from these, to get surfaces capable of 
adhering firmly to the new coat. This is best 
done on the polishing lathe, as in preparing new 
fittings. First wipe off all excess of dirt, grease 
or oil with a rag or cotton waste, then give the 
fittings to the polisher. Eusty fittings must re- 
ceive similar treatment. Old nickel may be 
removed from copper and brass fittings by strip- 
ping in acid. They must then be rinsed, dried 
and turned over to the polisher to be prepared. 
Old tinned fittings are scarcely worth the labor 
and expense of being re-nickeled, as they rarely 
look well after being stripped of their coat of 
nickel and tin. 



100 THE ELECTRO-PLATERS HAND-BOOK 

Working Nickel Solutions. Nickel solutions 
work best in large volumes of from 100. gallons 
upward, and these are contained in large tanks 
constructed to suit the work to be done in them. 
For instance, if long pieces of iron and steel, such 
as the shafting of machines or harness chains, 
have to be nickeled, the nickel solution may be 
contained in a long, narrow and shallow trough. 
If sheets of iron or such articles as stove-fronts 
form the bulk of the business, a thin and deep 
vat will be preferable. In such a vat a large 
number of small articles strung together on 
wires may be nickeled, such as screws or bicycle 
spokes, which can be wired by taking a turn of a 
long wire around each screw head, and thus mak- 
ing a long string of them. 

Double Salts of Nickel. The most important 
double salt of nickel is that of the double sulphate 
of nickel and ammonium. To prepare this, first 
make up a mixture of 1 part sulphuric acid, 2 
parts distilled water, and one-third part of nitric 
acid. Make this warm in a stoneware vessel on 
a fire furnished with a good flue to carry off the 
nitrous fumes, and add pure nickel until the 
acid ceases to dissolve any more of the metal. 
Drive off the excess acid, if any remains, by boil- 
ing the solution for a short time, dilute it with 
one-fourth its bulk of boiling water, and set 
aside to cool. When cool enough to filter, pass 
it through a linen filter into a vessel capable of 
holding double the bulk of liquid. Next dissolve 
some sulphate of ammonium in hot water until it 



ELECTRO-PLATING WITH NICKEL 101 

will not take up any of the ammonium salt, and 
set it aside to cool. Add the cold ammonium 
sulphate solution to the cold nickel sulphate solu- 
tion while stirring, until the nickel solution loses 
all its color and a copious precipitate of the 
double sulphate of nickel and ammonium has 
been thrown down to the bottom of the vessel. 
Pour off the supernatant liquid, and wash the 
crystals with a little more of the ammonium solu- 
tion. The crystals may now be dissolved in hot 
water and filtered. The resulting solution may 
be employed as the nickel bath, or may be evapo- 
rated down and set aside to cool, when the 
double salt will crvstallize out. 



Table Showing Rate of Nickel Deposition". 



Amperes of 


Square Feet 


Grains per 


Grains per 10 








Current. 


of Surface. 


Hour 


Hours 


Lbs. 



Ozs. 


Dnns. 


1 


.1 


16.756 


167.56 





6 


2 


o 


33.512 


335.12 


o 





12 


3 


.3 


50 . 26S 


502.68 





1 


2 


4 


.4 


67 . 024 


670 . 24 





1 


8 


5 


.5 


S3 . 7 SO 


S3 7. 80 





1 


14 


6 


.6 


100.536 


1005.36 





2 


4 


7 


.7 


117.292 


1172.92 





2 


10 


8 


.8 


134. 04S 


1340 . 4S 





3 


1 


9 


.9 


150.804 


1508.04 





3 


7 


10 


1.0 


167.560 


1675.60 





3 


12 


20 


2.0 


335 . 120 


3351.20 





( 


10 


30 


3.0 


502 . 6S0 


5026.80 





11 


7 


40 


4.0 


670 . 240 


6702.40 





15 


5 


50 


5.0 


837 . 800 


S37S.OO 


1 


3 


2 


60 


6.0 


1005.360 


10053.60 


1 


6 


15 


70 


7.0 


1172.920 


11729.20 


1 


10 


13 


80 


8.0 


1340.480 


13404.80 


1 


14 


10 


90 


9.0 


1508.040 


150S0.40 


2 


2 


7 


100 


10.0 


1675.600 


16756.00 


2 


6 


4 



102 THE ELECTRO-PLATERS HAND-BOOK 

Black Nickel-plating. It is possible to deposit 
a coating of nickel which will be a deep velvety- 
black and equally as hard and as thick as the 
ordinary nickel plating. The solution to pro- 
duce this result is as follows: Double sulphate 
of nickel acid 12 parts, aqua ammonia 16 parts, 
carbonate of ammonia 2 parts, arsenic 2 parts, 
cyanide of potassium (quantum sufficit) and suffi- 
cient water to make one gallon of solution. The 
water should not be added until all the chemicals 
are thoroughly dissolved. 

Boracic Acid. This is of use when the nickel- 
plating solution becomes muddy and dense, from 
becoming alkaline, so that the deposit is no longer 
white and tough. The acid should be used in 
the proportion of two ounces to the gallon of 
solution, and has the effect of clearing up the 
solution and whitening the deposit. 



ELECTRO-PLATING WITH SILVER 

To clean the work before plating, dissolve two 
ounces of lye to each gallon of boiling water, and 
dip the articles in hot, then scrub with a hard 
brush and fine powdered pumice stone, or pow- 
dered bath brick, or powdered Vienna lime, then 
wash in clean hot water, then in cold water. If 
the water adheres evenly all over, it is ready to 
plate, if it does not, then repeat the cleaning and 
scrubbing. 

After getting a slight coat of silver on the 
article it can be removed from the solution and 
scratch-brushed with the revolving scratch-brush, 
on which should be allowed to drip a little stale 
beer or soap suds, this lays down the grain of the 
silver, after which wash in clean hot and then 
cold water, and plate again. When sufficiently 
plated it can be scratch-brushed and buffed with 
the cotton flannel wheel, to which is applied a 
little powdered gold rouge mixed with alcohol 
into a paste. This gives the high color which 
takes the place of the more expensive hand bur- 
nishing. For plating silver on articles of iron or 
steel, it is well to give the articles a slight coat of 
copper from a cyanide of copper solution, which 
is very inexpensive. Another plan is to take, say 
1 quart of silver solution, when ready for use, 
and add 3 quarts of water to it and 6 ounces of 

103 



104 THE ELECTRO-PLATERS HAND-BOOK 

C. P. Cyanide of potash. Put in a large surface 
of silver and only a small surface of work at a 
time. The article will give off gas freely from 
this solution, before which it should be thor- 
oughly cleaned and pumiced, and a yellowish coat 
of silver will be deposited, which is very adhesive. 
From this put it in the regular silver solution to 
plate slowly until a sufficient deposit is obtained. 
From the work in the regular silver solution no 
gas should escape, otherwise a sandy, hard de- 
posit will b& the result. This can be regulated 
by the amount of anode immersed, distance 
between the anode and the work being plated, 
and the size of the wire, which can be reduced 
until sufficient resistance is introduced to prevent 
the escape of gas. 

Silver-plated Articles, Finishing of. When the 
articles have received a sufficiently thick deposit 
of silver, disconnect each from the connecting 
rod, one at a time, swill them in the plating solu- 
tion for a moment, drain off the solution taken by 
them from the bath, rinse each article well in 
clean hot water, and place at once in clean hot 
box-wood sawdust to dry. In this they should 
dry quite white. If they dry yellow or spotty, 
the cause may be traced to imperfect rinsing, or 
the use of soiled sawdust. When they are dry 
they should be taken to the scratch-brush and 
brushed until all the white burr or matt has been 
worked down. The brushes must not be worked 
dry, or they will stain the silver with brass, but 
must be kept wet with stale beer, This is best 



ELECTRO-PLATING WITH SILVER 105 

applied by means of a small drip-cock over the 
brush, attached to a lead pipe leading to a small 
cistern of stale beer placed over the lathe. Very 
little will be required to keep the brush moist, 
and the drips may be used over again if caught 
in a tray beneath the brush. The brush should 
either be made to revolve away from the work, or 
from left to right, to prevent splashing of the 
beer and snatching of the wcrk out of the oper- 
ator's hands by the brush. Only a very moderate 
pressure is required on the article to get its sur- 
face well brushed, slightly more pressure being 
necessary to force the wires of the brush into 
crevices. The brushes, as they come from the 
maker, are usually very stiff and the ends of the 
wires very sharp. In this condition they are apt 
to tear off some of the silver when first used. It 
is therefore advisable to break down the points 
by holding a piece of steel or cast iron to the 
revolving brush for a few minutes before using it 
on the silver-plated article. This wears down the 
sharpness of the freshly cut ends, and breaks the 
brush into a working condition. Brushes should, 
however, be selected to suit the class of work 
being done, the softer wires for thin coated goods 
and stiffer wires for more heavily coated and 
larger articles. When the articles have been 
scratch-brushed, they must be rinsed in clean 
water and again dried in sawdust preparatory to 
the next operations of polishing or burnishing. 

Polishing Silver Plate and Silver. The degree 
pf brightness or luster imparted to the surface 



106 THE ELECTRO-PLATERS HAND-BOOK 

of silrer-plated articles is insured by the number 
of processes through which it passes. A dull 
whiteness is left on the surface after scratch- 
brushing,, A better finish is given by the process 
of polishing. This is usually done on a polishing 
lathe, with similar buffs, bobs and circular- 
brushes to those employed in polishing the metal 
before plating. The lathe may be driven by foot 
power. A good lathe for this purpose is shown 
in Figure 17. 

Silver-plating Solutions, ^ever add anything 
to the solution except distilled water and cyanide 
of potassium when required. If the solution is 
too rich in silver for a given purpose, take out 
some of it and dilute the rest with distilled 
water. If it is not rich enough, do not add any 
other salt of silver except silver cyanide. Keep 
the solution covered up when not in use, to keep 
out dust and insects, and filter it through a filter 
made of well-washed linen. Shade the solution 
from direct sunlight, as this decomposes some of 
the silver salt and wastes the solution. Keep it 
as near as possible to a regular metal pitch, that 
is, with an approved quantity of silver in each 
gallon of solution, by working it with a sufficient 
anode surface and a sufficient quantity of free 
cyanide to dissolve the anodes freely. When the 
anode surface exposed to the action of the solu- 
tion exceeds slightly the surface of goods to be 
plated, and the solution contains a sufficient 
quantity of free cyanide, the current will dissolve 
from the anode as much silver as it deposits on 



ELECTRO-PLATING WITH SILVER 107 

the articles being plated. If, however, the con- 
trary conditions are present, the solution will be 
gradually impoverished, and the deposit show, 
sooner or later, the bad effects. It is quite pos- 
sible to err on the contrary side, and get a solu- 
tion too rich in silver from having too much free 
cyanide, or exposing too much anode surface to 
the solution. A lack of free cyanide is shown 
when the anode plates assume a hard, close-grained 
appearance, and are more or less coated with a 
dark, slimy deposit of silver oxide. An excess of 
free cyanide is shown on the anodes by their very 
white frosted surfaces being pitted and their 
edges ragged. It is also shown on the deposit by 
a soft, loosely deposited coat which strips under 
the scratch-brush and the burnisher. The odor of 
cyanide is also strongly pronounced, and this is 
mingled with an odor of ammonia in hot weather 
if much work is being done. In adding free 
cyanide, it is best to dissolve it in distilled water 
and filter the solution into the bath to remove any 
loose dirt held in the cyanide of potassium. 

Never swill freshly cleaned articles in the plat- 
ing solution, nor allow them to remain in the 
solution unless they form part of the plating cir- 
cuit and are receiving a deposit of silver, because 
the free cyanide will dissolve copper, brass, and 
other metals, and thus contaminate the solution 
with base metal. Solutions thus contaminated 
will not yield a pure white deposit of silver. 
Owing to such a large bulk of liquid being con- 
tained in a wooden vat, its temperature cannot 



108 THE ELECTRO-PLATERS HAND-BOOK 

be regulated, but the best results are obtained 
between 50 and 60 degrees Fahrenheit. 

Character of Silver Deposit. Electro-deposited 
silver is pure, if the silver employed in making 
up the solution is pure and the anodes are also 
pure. As the articles leave the solution coated 
with silver, their surfaces appear to have been 
whitewashed. The coat of pure silver upon them 
is composed of a number of fine grains beautifully 
massed and interlaced together. In this condi- 
tion they absorb the light, and have a peculiar 
dead white appearance, named matt in the plat- 
ing trade. If the solution is contaminated with 
copper or other base metal, or if the current is 
too dense, or if the solution is deficient in silver, 
or if the voltage of the current is too high, the 
deposit will have a hard and dark appearance, 
and will be intractable to the burnisher. If the 
current is too large, the silver will go on loosely 
in dark gray grains, and the deposit is said to be 
burnt. This may be prevented by interposing a 
resistance in the circuit, and thus checking the 
volume of current passing through the article 
being plated. It may also be prevented by mov- 
ing the article at a greater distance from the 
anode, or by placing more articles in the vat, or 
by lessening the anode surface exposed to the 
solution. If the voltage of the current is too 
high, the bad effects will be intensified, providing 
the volume of the current is also large, but a 
thin current with a high voltage will also deposit 
silver in a hard, dark condition, different from 



ELECTRO-PLATING WITH SILVER 109 

that above noticed. For this there is no other 
remedy except that of reducing the voltage by 
running the dynamo at a slower speed, or taking 
off some of the battery cells and reducing the 
number in series. If the hard, dark appearance of 
the deposit is due to a deficiency of silver in the 
solution, it must be remedied by adding more 
silver cyanide, or working with a weaker current 
and placing the articles nearer the anode. If the 
solution is contaminated with copper or other 
base metal, it is only fit for the most common 
work, and can only be remedied by turning it 
over to the refiner to be evaporated and reduced 
to old silver. One other cause of hard, dark sil- 
ver is due to the addition of brightening liquid 
to the solution, to get a bright deposit from it. 
A solution thus treated is spoiled for general 
work and will rarely recover its former con- 
dition. 

If silver-plated articles are exposed for a few 
minutes to the air and light after taking them 
from the bath, before rinsing them, the deposit 
will turn yellow. This is due to the action of 
light and air on the sub-cyanide of silver left on 
the surface. To prevent this, gently swill the 
articles to and fro for a few moments in the 
plating solution after disconnecting them from 
the cathode, rinse them at once in hot water and 
place them in hot, clean box wood sawdust. 
Extra care should be taken in this finishing oper- 
ation when the surface has to be left dead white 
instead of being polished or burnished. 



110 THE ELECTRO-PLATERS HAND-BOOK 

Thickness of Silver Deposits. It is not prac- 
ticable to gauge the thickness of a silver deposit 
with a pair of calipers, or even with a micrometer 
caliper gauge, but the thickness may be ascer- 
tained if its superficial area and weight are 
known. The first can be obtained by exact 



Table Showing the Rate of Silver Deposits. 



Square Feet 
Exposed. 


Rate of Cur- 
rent in Am- 
peres. 


Grains of Silver 

Deposited in One 

Hour. 


Grains of Silver 
Deposited in 
One Day of 
Ten Hours. 


.10 


1 


61.344 


613.44 


.20 


2 


122.688 


1226.88 


.30 


3 


184.032 


1840.32 


.40 


4 


245 . 376 


2453 . 76 


.50 


5 


306 . 720 


3067.20 


.60 


6 


368 . 064 


3680.64 


.70 


7 


429.408 


4294.08 


.80 


8 


490 . 752 


4907.52 


.90 


9 


552 . 096 


5520.96 


1.00 


10 


613.440 


6134.40 


2.00 


20 


1226.880 


12268.80 


3.00 


30 


1840.320 


18403.20 


4.00 


40 


2453 . 760 


24537 . 60 


5.00 


50 


3067 . 200 


30672.00 


6.00 


60 


3680 . 640 


36806.40 


7.00 


70 


4294 . 080 


42940.80 


8.00 


80 


4907.520 


49075 . 20 


9.00 


90 


5520.960 


55209.60 


10.00 


100 


6134.400 


61344.00 



measurement and calculation, and the next by 
noting the difference between the weight of the 
article both before and after plating. The 
weight of silver may also be approximately known 
by noting the volume of current passing through 
the solution in a given time. Thus it takes one 



ELECTRO-PLATING WITH SILVER 111 

ampere of current per second to deposit .017064 
grains of silver. If this volume of current 
passes through the solution for one hour, it 
should deposit 61.344 grains of silver, and this 
should be the weight of silver acquired by the 
article. If the coated surface be measured, the 
thickness of the silver coat may be accurately 
obtained. The following calculations may help 
the plater to determine the thickness of the silver 
deposit. 

Upon referring to the table the plater can 
ascertain at a glance how much current will be 
required to coat a surface with silver, or how 
much surface a certain volume of current will 
coat properly, or how much silver will be de- 
posited by a known volume of current in a given 
time. It should be clearly understood, however, 
that the above figures relate solely to the actual 
volume of current passing through a solution as 
measured bv an ammeter in circuit, but not to 
the mere capacity of the generator as ascertained 
by measurement of the current on short circuit 
between its poles. When dynamos are advertised 
as having a capacity of so many amperes or so 
many ounces of silver per hour, the figures 
merely give an idea of their maximum output, 
without reference to the resistance of the circuit. 
The maximum current obtainable from a dynamo 
can only be made available in depositing silver 
when the resistance of the conducting wire Is 
low, and the full surfaces of anode and cathode 
are exposed to the plating solution. 



112 THE ELECTRO-PLATERS HAND-BOOK 

Bright Silver-plating. Silver is deposited from 
a silver-plating solution in a matt condition with- 
out luster, and is afterwards made bright by 
scratch-brushing, polishing and burnishing. It 
is sometimes desirable to deposit silver in a bright 
condition, upon parts that will not admit of being 
burnished. This is effected by adding a solution 
of carbon bisulphide to the plating solution and 
stirring it in well some hours before the opera- 
tion of plating. The following is a most con- 
venient method for preparing a brightening 
solution. Procure one quart of old silver solu- 
tion, place it in a bottle capable of holding two 
quarts and furnished with a glass stopper. Add 
to this two fluid ounces of carbon bisulphide, 
place the stopper in the bottle and shake well 
together, then nearly fill the bottle with a strong 
solution of potassium cyanide, again shake well 
together, and then set aside in a cool place for 
twenty-four hours. The solution for bright plat- 
ing should either be an old one, or one set aside 
for the purpose. To this add two fluid ounces of 
the brightening solution as often as may be re- 
quired. Too much of this will spoil the plating 
solution, and the deposit of silver will be brown- 
ish or spotted with brown spots. The bright 
deposit spreads from the lower parts of the 
articles upward until all has been covered. It is 
darker than ordinary silver, and the somber hue 
deepens after the article has been removed from 
the solution unless well rinsed in boiling water. 
Bisulphide of carbon has a. noxious odor and its 



ELECTRO-PLATING WITH SILVER 113 

vapor is inflammable and highly poisonous. It 
should therefore be used with caution and kept in 
a closely stoppered bottle in a cool place. Its 
solution with cyanide of potassium gradually 
turns black, but the blackness may be lessened by 
adding plenty of free cyanide. 

Nitrate of Silver. This is the salt of silver 
used in making up silver-plating solutions. 
Other salts, such as the chloride, sulphide, oxide, 
sulphite, hyposulphite, acetate, iodide, and 
chromate of silver, may be mentioned, but most 
of them are made from the nitrate of silver, and 
all except this one are unsuitable for conversion 
into cyanide of silver on account of the bad effects 
of the by-products formed in the process of con- 
version. In using nitrate of silver there is no 
waste, since the salt is perfectly soluble in dis- 
tilled water, from which all the silver can be pre- 
cipitated as a single cyanide of silver. The 
nitrate can be cheaply and easily made, and can 
also be purchased at a reasonably low price in a 
state of purity. 

It must be understood that only perfectly pure 
silver is admissible in a silver-plating solution. 
Standard silver is useless, because this contains 
copper, as does also nearly all commercial silver, 
but alloyed silver may be refined by the plater 
and then converted into the pure silver nitrate. 
But. if pure nitrate of silver is desired, pure sil- 
ver in the form of silver foil or grain silver must 
be had. This obtained, dissolve the pure metal 
in a warm mixture of 4 parts of pure nitric acid 



114 THE ELECTRO-PLATERS HAND-BOOK 

and 1 part of distilled water and evaporate off all 
excess of acid to form the desired silver salt. As 
this may still contain some free acid, it is advis- 
able to dissolve the salt in distilled water and 
again evaporate and re-crystallize the silver 
nitrate. If now the salt contains any copper, it 
will be shown on the sides of the evaporating dish 
in greenish or slightly blue streaks and spots. 
To demonstrate the presence of copper, dissolve 
a small portion of the nitrate of silver in a test 
tube with a little distilled water and add to it a 
few drops of diluted liquor ammonia. If copper 
is present in the nitrate solution, a blue ring will 
be formed in the test tube where the ammonia 
meets the nitrate of copper, and the intensity of 
this blue ring will show at once whether the cop- 
per is present in a large or in a small quantity. 
If copper is detected, the whole mass of silver 
nitrate must be dissolved in distilled water, and 
common salt (sodium chloride) added as long as 
a white precipitate of silver chloride is thrown 
down. The liquid above this will contain all the 
copper in the form of copper chloride, and as this 
is soluble in water, while the silver chloride is 
not, the two may be entirely separated by pouring 
away the supernatant liquor and washing the sil- 
ver chloride several times in an abundance of 
clean hot water. This is done by pouring dis- 
tilled water into the vessel containing the silver 
chloride, stirring it up well with a glass rod, 
allowing the white powder to subside and then 
pouring off the water. It is not necessary to 



ELECTRO-PLATING WITH SILVER 115 

pour off the last few drops of water each time, 
and at the last some of it may be left to cover the 
precipitate, and to this should be added a small 
quantity of hydrochloric acid. Some clean 
scraps of zinc or some granulated zinc must now 
be well stirred into the silver chloride precipitate 
and frequently moved about in it. The chlorine 
in the silver chloride, having a stronger affinity 
for zinc than it has for silver, will now leave the 
silver in the form of very small gray grains and 
combine with the zinc to form soluble zinc 
chloride. When all the silver chloride has been 
thus decomposed, and not a trace of the white 
precipitate remains, stir in a little more hydro- 
chloric acid and pour off the zinc chloride solu- 
tion. Next add equal parts of hydrochloric acid 
and water to the gray mass remaining, and stir 
up well for several minutes to completely dissolve 
the last trace of zinc remaining entangled in the 
silver grains and finally well wash the mass in an 
abundance of water, using distilled water for the 
last two washings. The gray, wet mass should 
now be perfectly pure silver, which may be dried 
and melted in a crucible under a layer of char- 
coal, or dissolved at once in dilute nitric acid to 
form silver nitrate. 

This operation must be performed in a cup- 
board, or in a fireplace with- a very good draught 
to carry away the highly poisonous fumes of 
nitrous oxide thrown off from the solution. It is 
best carried on in a porcelain beaker or an evap- 
orating dish over a sand bath heated by a small 



116 THE ELECTRO-PLATERS HAND-BOOK 

gas stove. Only enough acid should be employed 
to dissolve all the silver, as all excess acid will be 
wasted. The right quantity is about four fluid 
ounces of acid and one of distilled water to each 
ounce of silver. The heat applied should be very 
moderate at first, until all the silver has been 
dissolved, then increased to evaporate the excess 
of water and acid, but in no case should the solu- 
tion be allowed to boil. When it has become 
thick it may be taken off the stove and set aside 
to cool. As the thick liquor cools it will congeal 
to a mass of crystals, and these may hold some 
free acid. This may be removed by dissolving 
the crystals in distilled water and evaporating 
the solution again. All free acid left in a silver 
nitrate solution means a corresponding loss of 
silver and of cyanide when making up the cyanide 
of silver solution, as the acid decomposes part of 
the cyanide of potassium, converting it into 
nitrate of potash and free cyanide gas, while some 
of the silver is left in the solution. 

Cyanide of Silver. The single cyanide of silver 
is prepared from nitrate of silver by adding a 
solution of cyanide of potassium to a solution of 
silver nitrate as long as a precipitate is formed. 
This precipitate is in the form of small white 
grains and is composed of one equivalent of sil- 
ver, 108 parts, added to one equivalent of cyano- 
gen, 26 parts, making cyanide of silver having a 
molecular weight of 134. The action which 
takes places on adding the two solutions is as 
follows: Potassium cvanide added to silver 



ELECTRO-PLATING WITH SILVER 117 

nitrate exchanges its cyanogen for the nitrogen 
and oxygen of the silver nitrate and becomes 
nitrate of potash, whilst the cyanogen unites with 
an equivalent of silver to form silver cyanide. As 
nitrate of potash is soluble in water and cyanide 
of silver is not soluble in water, it is only neces- 
sary to pour off the supernatant liquor and wash 
the precipitate in water to obtain pure cyanide of 
silver. 

The most practical method of making silver 
cyanide for electro-plating purposes is as follows : 
Dissolve the silver nitrate in distilled water or in 
clean rain water in the proportion of 1-J- ounces 
troy of the salt in half a gallon of water. Next 
make a solution of cyanide of potassium in dis- 
tilled water or in clean rain water in the propor- 
tion of one ounce troy of 90 per cent cyanide to 
one quart of water. Add this gradually, with 
frequent stirring, to the silver nitrate solution, 
pouring in the last few drams carefully and 
noting the result. If the precipitate settles down 
and leaves the supernatant liquid clear, enough 
cyanide has been added, but if the liquid is 
cloudy, make up some more cyanide solution and 
add this drop by drop until the cloudy appearance 
has been removed. If too much cyanide is added 
it will dissolve some of the precipitate and give a 
slightly brown tint to the supernatant liquid as it 
passes through. In this case add a few drops of 
silver nitrate solution until it ceases to form a 
white, cloudy precipitate. This operation is best 
carried en in a glass vessel, such as a bell glass 



118 THE ELECTRO-PLATERS HAND-BOOK 

fixed in a stand of wood, or in the glass cell of an 
accumulator. When all the precipitate has set- 
tled down, the supernatant liquor must be poured 
of! into another vessel and treated for recovery of 
silver, and the silver cyanide well washed with 
water. It is then ready to be dissolved in a 
strong cyanide solution to form the plating bath, 
or may be dried gently on a water bath and be 
stored away in glass jars for future use. Cyanide 
of silver is insoluble in water and in cold nitric 
acid, but is freely soluble in solutions of ammonia, 
carbonate of ammonia, nitrate of ammonia, sal- 
ammoniac, hyposulphite of soda, the cyanides of 
ammonium, sodium, and potassium, ferro- cyanide 
of potassium, and in solutions of the alkaline 
chlorides. Hydrochloric acid decomposes it with 
an evolution of hydrocyanic acid gas. Boiling 
sulphuric acid and water has a similar effect, and 
produces a formation of silver sulphate. The 
gas given off in these reactions is dangerously 
poisonous and must not be inhaled, as its effects 
are identical with those of prussic acid. It must 
be also understood that all the cyanides are 
equally dangerous poisons and must be used with 
great care to avoid fatal consequences. 

Double Cyanide of Silver and Potassium. This 
salt, dissolved in distilled water, forms the best 
solution for silver-plating purposes. It is formed 
by dissolving an equivalent of silver cyanide, 134 
parts, in a solution containing an equivalent of 
pure cyanide of potassium, 65 parts, the resulting 
salt being composed of one equivalent of silver, 



ELECTRO-PLATING WITH SILVER 119 

108 parts, one equivalent of potassium, 39 parts, 
and two equivalents of cyanogen, 52 parts, mak- 
ing together a double salt having the molecular 
weight 199. 

In practice, the silver-plating solution of this 
salt is formed by dissolving the wet cyanide of 
silver, freshly prepared, in a solution containing 
as much cyanide of potassium as it takes to 
throw down the silver cyanide, and then adding 
about one-fifth more of potassium cyanide to 
form free cyanide, this excess being necessary to 
dissolve the silver anode and keep the solution in 
working order. This solution is then made up 
with distilled water so as to contain a certain 
weight of silver per gallon, which may vary from 
half an ounce up to 5 ounces or more to the gallon. 

The variation in the strengths of silver-plating 
solutions adopted by platers is regulated by the 
special requirements of the trade in which each 
workman is employed. Attenuated solutions con- 
taining from one-quarter ounce to one ounce of 
silver in the gallon, deposit their silver more 
slowly than rich solutions containing from 4 
ounces to 6 ounces of silver in the gallon, but the 
deposit from each and all may be equally good. 
As weak solutions are bad conductors of the cur- 
rent, a higher voltage must be employed to force 
the current through them than will be found 
necessary in richer solutions. The amount of 
silver per gallon may be determined at the outset 
by reckoning each 170 ounces of silver nitrate to 
yield 108 ounces of pure silver. 



120 THE ELECTRO-PLATERS HAND-BOOK 

The quantity of excess cyanide of potassium in 
each gallon of solution also varies with the 
requirements of the work to be done in the solu- 
tion. This should, however, be lessened if such 
metals as bare copper, coppered zinc, coppered 
iron, or any other metal or alloy on which 
cyanide of potassium acts quickly, or on which 
silver is readily deposited from its plating solu- 
tion, is to be plated in the solution. It is just in 
such instances as these where quickening the sur- 
face with mercury comes in useful. It is possible 
to so arrange the proportion of free cyanide in a 
solution as to suit exactly one class of work and 
to deposit an adherent coat of silver in this class 
without quickening the surface, but it is not always 
convenient to do so. 



ELECTRO-PLATING WITH GOLD 

Gold is easily electro-deposited from all its solu- 
tions by a small current of electricity, but the 
deposits of gold are not all equally good from all 
solutions. Although it is a metal easily de- 
posited, there is no other capable of such an infi- 
nite variety in the color and character of the 
deposit. This varies with the character of the 
solution from which it was deposited, the tem- 
perature of the solution at the time of deposition, 
and the current employed to deposit the metal. 
As gold is deposited from its solution in potas- 
sium cyanide in good condition and color, this 
solution has become the general favorite with 
electro-gilders. 

Terchloride of Gold. As this soluble salt of 
gold can be readily prepared, it is used generally 
in making up gold solutions. It is easily made 
by dissolving pure gold in a solution of aqua regia, 
evaporating the excess of acid and continuing the 
heat until the salt forms ruby red crystals on the 
sides of the evaporating dish. The details of this 
process are as follow : Make up a mixture of 3 
parts of pure hydrochloric acid, 1 part of pure 
nitric acid, and 1 part of distilled water, to dis- 
solve 1 part of pure gold, that is to say, it will 
take 6 fluid ounces of this mixture to dissolve 1 
Troy ounce of pure gold. The acid mixture must 

121 



122 THE ELECTRO-PLATERS HAND-BOOK 

be placed in a large glass beaker or large porcelain 
evaporating dish, over a sand bath or water bath, 
in a cupboard or in some place where the highly 
poisonous and corrosive fumes of the mixture can 
be carried away by a strong draught. Heat must 
then be applied to the sand bath until the mix- 
ture becomes warm, when the gold must be added 
in small quantities at a time until all the gold is 
dissolved or the warm acid ceases to take up any 
more. During this operation dense brown fumes 
of a penetrating, pungent and strongly corrosive 
character will be given off from the mixture. 
The heat must be continued below boiling point, 
until all excess of acid and water has been driven 
off in the form of steam and only a dark, thick 
liquid remains at the bottom of the evaporating 
dish. The operator should protect his hands 
with a pair of thick gloves, and then proceed to 
turn the dish about, tilting it from side to side 
until the dark liquid all crystallizes on the sides 
of the dish in the form of ruby red crystals. The 
whole contents of the dish should then be dis- 
solved in hot distilled water and set aside to cool, 
when it must be filtered through blotting paper 
to remove any dirt contracted in the previous 
process. If any brown powder remains at the 
bottom of the dish, it is in all probability finely 
divided gold, and this must be dissolved in a little 
more of the acid mixture and treated like the 
bulk of the sample. As gold is a very precious 
metal, great care must be exercised to avoid 
waste, and all rinsings of the vessels, together 



ELECTRO-PLATING WITH GOLD 123 

with washings of the filter, mast be made with 
distilled water and then added to the filtered solu- 
tion. The terchloride of gold solution thus made 
may be again evaporated over a water-bath at a 
low temperature, and the dried salt stored away 
in wide mouthed bottles, or the solution may be 
diluted with distilled water and treated direct 
with cyanide of potassium to form gold cyanide. 

Terchloride of gold is formed of three equiva- 
lents of chlorine (35.5 x 3) added to one equiva- 
lent (197) of gold, and has, therefore, the 
molecular weight 302.15. It is very soluble 
in water and its solution stains the skin a dark 
purple tint. 

Cyanide of Gold. Cyanide of gold is formed as 
a yellow precipitate when a solution of cyanide of 
potassium is added to a solution of terchloride of 
gold in distilled water. The precipitate forms 
slowly and falls tardily. In making cyanide of 
gold, the terchloride solution should be largely 
diluted with distilled water, so as to contain not 
more than one ounce of gold in half a gallon of 
water, and the solution of cyanide should also be 
very dilute to produce good results. If the 
terchloride solution is too dense, or contains any 
free acid, or the cyanide solution is too strong, a 
large proportion of the gold will enter into com- 
bination with the cyanide of potassium to form a 
double soluble salt of gold and potassium, and 
thus be taken up by the supernatant liquid. 
Even when the greatest care is exercised in mak- 
ing this salt, some gold is found in the super- 



124 THE ELECTRO-PLATERS HAND-BOOK 

natant liquid and in the wash waters. These 
should be carefully preserved and treated for the 
recovery of the gold. The details of the process 
for making cyanide of gold are precisely the same 
as those for making cyanide of silver, but, owing 
to the difficulties experienced in determining the 
end of the process, and the loss of metal likely 
to be sustained by the operation, it should only 
be undertaken by experienced persons. 

Double Cyanide of Gold and Potassium. When 
an excess of cyanide of potassium solution is 
added to the yellow cyanide of gold precipitate, 
it dissolves and forms a solution containing the 
double cyanide of gold and potassium. If the 
gold cyanide has been properly prepared and 
washed, as directed for the silver cyanide, this 
solution is undoubtedly the best for electro- 
gilding. 

The double cyanide of gold is composed of one 
equivalent of gold and one equivalent of potas- 
sium added to two equivalents of cyanogen. But 
the gilding solutions made by inexperienced 
operators usually contain a large addition of 
chloride of potash, formed whilst attempting to 
throw down the gold cyanide. 

Owing to the difficulty experienced by many 
operators in precipitating the cyanide of gold, 
many makeshifts have been resortel to with a 
view to avoid having chloride of potash in solu- 
tion. If an excess of liquid ammonia is added to 
a solution of terchloride of gold, a brown pre- 
cipitate is formed. This is an oxide of gold, hav- 



ELECTRO-PLATING WITH GOLD 125_ 

ing dangerously fulminating properties when 
dried, as it will then explode violently if heated 
or subjected to friction. This precipitate must 
therefore be well washed and dissolved whilst wet 
in a solution of potassium cyanide to form the 
gilding bath. It must then be boiled for several 
minutes to expel the ammonia still held in the 
solution. This is a fairly good solution, yielding 
a rich gold deposit when first made up, but liable 
to deposit a darker gold as it gets older. As it is 
made from oxide of gold dissolved in cyanide of 
potassium, it contains an oxide of potash in addi- 
tion to the double salt of gold and potassium. 
The same is true of all solutions made from oxide 
of gold, which may be prepared in another way by 
adding calcined magnesia to the terchloride of 
gold solution as long as a brown precipitate falls. 
This must be removed from the solution by filtra- 
tion, and then digested in dilute nitric acid to 
remove the excess magnesia. The gold oxide 
must then be well washed to remove the last 
trace of acid, and dissolved in a solution of 
cyanide of potassium to form the gilding bath in 
the usual manner. 

Another solution may be made by first throw- 
ing down all the gold as a precipitate from its 
terchloride solution by adding sulphide of ammo- 
nium. This precipitate is to be well washed and 
dissolved while wet in a solution of cyanide of 
potassium to form the gilding bath. It must 
then be boiled for half an hour to expel the excess 
ammonia, and the loss due to evaporation made 



126 THE ELECTRO-PLATERS HAND-BOOK 

up with distilled water. With a moderate excess 
of free cyanide, this solution will yield a fine 
color when worked at a temperature of 130 de- 
grees Fahrenheit, and will give good results for a 
considerable period. 

Characteristics of Gold Deposits. When gold is 
deposited from a cold or cool solution it has a 
paler tint and is less coherent than when de- 
posited from a hot solution. A rise in tempera- 
ture causes the gold to be deposited faster and 
assume a brown tint, which disappears on scratch- 
brushing the article. Movement of the article being 
gilded has a tendency to prevent this dark brown 
appearance and cause a lighter colored deposit. 
If a thick deposit is desired, the article should be 
taken from the bath every few minutes, scratch- 
brushed to remove the brown appearance, and 
returned to the bath for another coat. 

Gilding Bath, Strength of. Gilding baths will 
yield good results with only 5 pennyweights of 
gold in each gallon of solution, if worked under 
suitable conditions, or they will yield equally 
good deposits with one ounce or more of gold in 
each gallon of solution. A very good working 
strength is insured with from 10 to 15 penny- 
weights of gold to the gallon. Solutions poor in 
gold are liable to great fluctuations in the color 
of the deposit, which will assume a dark, hard 
appearance, resembling 15-carat gold, if the bat- 
tery voltage is too high. A similar appearance 
will result from the presence of too much free 
cyanide. A great excess of free cyanide will 



ELECTRO-PLATING WITH GOLD 127 

cause the gold deposit to assume a foxy-red tint, 
which cannot be altered by subsequent scratch- 
brushing and polishing. Solutions too rich in 
gold, deposit the metal too fast, and in a non- 
coherent condition liable to strip under the bur- 
nisher. This condition is intensified if the 
solution contains an excess of free cyanide in 
addition to an excess of gold. 

Polishing and Finishing Electro-gilt Articles. 
After the articles have received the desired coat 
of gold, they should be rinsed in clean warm 
water and scratch-brushed whilst wet, then pol- 
ished and finished. If it is necessary to burnish 
parts of the work, full directions for this process 
will be found. 

Assaying Gold and Silver Solntions. The exact 
strength of a gold or silver solution may be ascer- 
tained in the following manner : Take one fluid 
ounce of the solution and evaporate it to dryness 
in a porcelain dish, in a sand bath over a small 
gas stove. To the dried salt add an equal bulk 
of litharge and mix the whole well together. 
Calcine the mixture in a small crucible and keep 
it at a glowing red heat until all the litharge has 
been decomposed and a small pool of molten lead 
appears at the bottom of the crucible. This lead 
will contain all the silver or gold in the sample 
to be assayed, and must be poured out on a clean 
iron slab to cool. The button of lead must now 
be placed on a boneash cupel (a small cup of 
boneash) and subjected to a strong heat in the 
presence of air until all the lead has been oxidized 



128 THE ELECTRO-PLATERS HAND-BOOK 

and absorbed into the boneash of the cupel and 
only a button of pure gold or pure silver remains. 
This must be allowed to cool on the cupel, from 
which it can be easily detached, then cleaned 
from adhering boneash and exactly weighed. 
The weight of the button thus obtained should 
be of T J-^ that of the silver or gold in a gallon of 
the solution, therefore if the weight is multiplied 
by 160 (the number of fluid ounces in a gallon), 
the exact weight of precious metal in a gallon will 
be obtained. 



ELECTRO-PLATING WITH COPPER 

Copper is deposited from an acid solution of 
copper sulphate in the various processes of elec- 
trotyping and copying artistic objects in this 
metal. The deposits thus obtained are removable 
from the moulds on which they are deposited, 
and afterwards have a separate existence of their 
own. The process of obtaining them, therefore, 
cannot be deemed a branch of electro-plating 
proper, but forms a separate art. Copper is em- 
ployed chiefly as a coating on such metals as iron, 
steel, zinc, tin, lead, pewter, and white metal 
when preparing these to receive a deposit of sil- 
ver, because silver will not adhere perfectly to 
iron, steel, zinc, tin, or lead when deposited upon 
these metals direct, but will adhere perfectly to 
copper when deposited on these metals, and cop- 
per can be made to adhere firmly to each and all 
of them. A coat of copper is also preferred by 
some platers on such alloys of tin and lead as 
pewter and white metal before these are plated 
with silver, because a firm and adherent deposit 
of silver can only be obtained on these alloys by 
spcial precautions taken in their preparation. It 
is also deposited on articles made of iron and of 
zinc, and the coating is subsequently subjected to 
the action of acids to produce bronzing effects on 
the copper coating. It is likewise employed as a 

129 



130 THE ELECTRO-PLATERS HAND-BOOK 

preparatory coating to a deposit of gold and of 
nickel on the above-named metals, although this 
is not always necessary, since gold and nickel can 
be firmly deposited on iron, steel, zinc, etc., 
without the intervention of copper. 

Alkaline Solutions of Copper. As all acid solu- 
tions of copper, even the saturated solution of 
copper sulphate, deposit their metal on iron, 
steel, zinc, lead, and its alloys by simple immer- 
sion or chemical displacement, they are unsuitable 
as depositing solutions for electroplating with 
Copper, since such deposits are never firmly 
adherent to the metal on which they are de- 
posited. We have therefore to employ an alka- 
line solution which will not deposit its metal by 
simple immersion on those we wish to cover. 
Several various solutions have been employed, 
among which may be mentioned a solution of 
cyanide of copper and bisulphite of sodium, a 
solution of bitartrate of potash and carbonate of 
copper, a solution of cyanide of copper and tar- 
trate of ammonia, a solution of phosphate of cop- 
per and ammonia, and also a solution of sulphate 
of copper, tartrate of potash and caustic soda. 

Cyanide of Copper Solution. The solution in 
general use for coppering iron and zinc is that of 
the double cyanide of copper and potassium. 
This may be readily prepared by the battery 
process, as directed for preparing gold solutions, 
using an anode of pure copper in a hot solution 
of cyanide of potassium. Or it may be prepared 
by throwing down the copper from any of its acid 



ELECTRO-PLATING WITH COPPER 131 

solutions, as cyanide of copper, and then dissolv- 
ing this in a solution of potassium cyanide, by the 
process given for making up the solution of 
double cyanide of silver and potassium. This 
solution possesses the disadvantage of having to 
be used at a temperature of from 160 to 180 de- 
grees Fahrenheit, and it does not freely dissolve 
the anode unless a large excess of free cyanide is 
present in the solution, and this excess is detri- 
mental to the deposit of copper, since it has a 
tendency to dissolve the newly deposited coat and 
make it loose or spongy. 

Alkaline Copper Solution. The best alkaline 
copper solution is made as follows: Dissolve 
eight ounces of copper sulphate in one quart of 
hot rain or distilled water and set aside to cool. 
When cool, add liquid ammonia, whilst stirring 
with a stick or glass rod. At first a green pre- 
cipitate will fall, and then this will dissolve on 
adding more ammonia, until the whole solution 
assumes a blue tint. Dilute this with an equal 
bulk of cold rain water and add to it enough 
solution of potassium cyanide, whilst stirring, to 
destroy the blue color of the ammonia sulphate 
and give the color of old ale to the solution. Set 
this aside for a few hours, then pass it through a 
linen filter and make it up to a gallon of solution 
with rain or distilled water. This solution may 
be worked cold, but the rate of deposition is in- 
creased and the deposited copper of improved 
quality when the solution is heated to a tempera- 
ture of from 110 to 130 degrees Fahrenheit. 



132 THE ELECTRO-PLATERS HAND-BOOK 

Working Alkaline Copper Solutions. As the 
affinity between copper and cyanide is stronger 
than that between copper and acid, it takes a 
higher voltage to separate them and deposit the 
copper in good condition. Copper may be de- 
posited from an acid solution with a voltage of 
less than 1 volt, but it takes a voltage of from 6 
to 8 volts to deposit copper on iron from an alka- 
line solution. Gas must be freely given off from 
the article whilst deposition is proceeding, but 
the volume of gas must be reduced by reducing 
the voltage of the current if the deposit shows a 
tendency to become dark and sandy. An anode 
of pure copper must always be employed. If the 
anode coats itself with a green crust soon after 
deposition commences, add some liquid am- 
monia, whilst stirring the solution, until the 
green crust dissolves and the anode works clean. 
If the anode becomes coated with a blue crust, 
add cyanide of potassium solution. By thus 
noting the condition of the anode and adding 
ammonia or cyanide as required from time to 
time, the solution may be kept in working order. 
It is not usual to deposit thick coats of copper 
from alkaline copper solutions, but to just cover 
the article with copper and then transfer it at 
once to the plating solution before the pure cop- 
per coat can become oxidized by the action of the 
air. When thick deposits of copper are required, 
the articles are transferred from the copper 
plating bath at once to an acid solution of cop- 
per sulphate, and deposition continued in this 



ELECTRO-PLATING WITH COPPER 133 

until the desired thickness of copper has been 
obtained. 

Rate and Thickness of Copper Deposits. Cop- 
per is deposited from its solutions in good condi- 
tion at the rate of .05045354 grains per second 
with 1 ampere of current, or at the rate of 18.1G3 
grains per ampere-hour. With 1 ampere of cur- 
rent depositing copper on one-tenth of a square 
foot of surface, 181.63 grains are deposited in 10 
hours, while with 10 amperes of current 181.63 
grains of copper are deposited on 1 square foot 
of surface in 1 hour, and with 100 amperes 
1816.3 grains of copper are deposited per hour. 
The rate of deposit suitable for a known surface 
can thus be readily ascertained, together with the 
volume of current necessary to effect the desired 
deposit in a given time, bearing in mind always 
that to force copper rapidly on a small surface it 
will be necessary to increase the voltage of the 
current, and this may deposit brittle metal. The 
thickness of a copper deposit may be ascertained 
by calculating each 2.2468 grains per square inch 
to measure one-thousandth of an inch in thick- 
ness. 



ELECTRO-PLATING WITH ZINC, TIN, IRON 
AND PLATINUM 

Electro-plating with Zinc. Zinc has been elec- 
tro-deposited from a solution of its sulphate by 
the use of a feeble current. It has also been 
deposited from its solutions of chloride, acetate, 
tartrate, ammonia sulphate, and ammonia 
chloride. 

Zinc-plating Solution. Dissolve 200 ounces of 
best cyanide of potassium in 20 gallons of water 
and stir into this 80 ounces of strong liquid am- 
monia. Place several large, clean, porous cells in 
the solution, and fill these with the bath liquid. 
In each cell suspend a strip of copper, and con- 
nect each strip to the negative pole of a strong 
battery or a plating dynamo. From the other 
pole suspend a large anode of zinc and pass a cur- 
rent until 60 ounces of zinc have been dissolved 
from the anode. Next dissolve 80 ounces of car- 
bonate of potash in part of the bath solution, stir 
this into the main bulk and let it rest for 12 
hours. Filter the bath before using and work it 
with a current of from 4 to 5 volts, using anodes 
of milled zinc. The articles to be zinc-plated 
should be cleaned and treated as for silver-plat- 
ing, but not quickened in mercury. 

Tin-plating. The so-called tin vessels com- 
monly in use for domestic and other purposes are 
134 



ZINC, TIN, IRON AND PLATINUM 135 

made of thin sheet iron coated with tin. The 
sheets of iron are dipped in a bath of molten tin, 
and thus acquire a thin film of this metal. The 
insides of copper and iron vessels employed for 
culinary purposes are coated with tin by a similar 
process. Whenever it is deemed desirable to coat 
an article with tin, it may be cheaply and expe- 
ditiously done by this, the molten process. Small 
brass articles, such as pins, hooks and eyes, and 
small copper articles, such as hooks and buttons, 
may be easily coated with tin by simple immersion 
in a bath composed of a saturated solution of 
cream of tartar in which has been dissolved a 
small quantity of chloride of tin. The quantity 
of this salt is immaterial, as it is only employed 
to start the process, the remaining tin being sup- 
plied from anodes of sheet tin suspended in the 
bath. The liquid is kept at a boiling tempera- 
ture and the articles to be tinned are suspended 
in the bath between the tin anodes until suffi- 
ciently whitened, when they are rinsed in water 
and rattled about in hot bran until dry and 
bright. Iron articles may be similarly whitened 
in a boiling solution made by dissolving 3 drams 
of fused protochloride of tin and 6 ounces of 
ammonia alum in one and a quarter gallons of 
water. Bronze may be coated with tin in a hot 
solution of caustic soda in contact with anodes of 
pure tin. 

Electro-plating with Tin. Tin may be readily 
deposited by the single cell process from its solu- 
tion in caustic soda or in caustic potash. Make 



136 THE ELECTRO-PLATERS HAND-BOOK 

up a strong solution of either of those caustic 
alkalies, and add to it a small quantity of per- 
chloride of tin, also put some plates of pure tin 
in the cell. Place some of the caustic alkali solu- 
tion in porous cells with strips or bars of zinc, and 
connect the articles to be tinned to copper wires 
attached to the zinc and immerse the whole in 
the tinning solution. Solutions for the electro- 
deposition of tin with current frcm a separate 
battery are here given. Solution No. 1 is made 
in the following manner: Dissolve 30 pounds of 
caustic potash in 20 gallons of water, 30 pounds 
of cyanide of potassium in 20 gallons of water, 
and 30 pounds of pyrophosphate of soda in 60 
gallons of water. Into the caustic potash solu- 
tion pour gently, whilst stirring all the time with 
a glass rod, 200 fluid ounces of the chloride of tin 
solution, then all the cyanide solution, and lastly 
all the soda solution. This solution is used for 
tinning zinc articles and is worked at a tempera- 
ture of 70 degrees Fahrenheit, with a current 
having an electromotive force of from 3 to 4 volts. 
Solution No. 2 is made up of 20 pounds pyrophos- 
phate of soda dissolved in 40 gallons of water info 
which is poured 100 fluid ounces of the chloride 
of tin solution, and, finally, there is added 
to this 56 pounds of sal-ammoniac dissolved 
in 60 gallons of water. This solution may 
be worked with a weaker current than that 
employed for No 1 solution, but must be used 
at a temperature of from 100 to 110 degrees 
Fahrenheit, 



ZINC, TIN, IRON AND PLATINUM 137 

Electro-plating with Iron. Iron may be de- 
posited from suitable solutions, in a condition 
resembling hard steel, and in this state has been 
found useful for facing printers' type, engraved 
copper plates, and electrotypes of copper. The 
process has been named acierage, or steel-facing. 
Various solutions have been tried for the purpose. 
One solution is made as follows : Dissolve a 
quantity of iron sulphate in water and add a solu- 
tion of ammonia carbonate until all the iron has 
been thrown down. Wash the precipitate several 
times, and dissolve it in sulphuric acid, taking 
care to only add as much acid as will dissolve the 
precipitate. Use this solution in a concentrated 
state, with iron anodes having a combined surface 
some seven or eight times larger than the copper 
surface to be coated. The bath must not be 
allowed to get acid, so it must be kept well sup- 
plied with iron, and it is advisable to add car- 
bonate of ammonia occasionally. The copper 
plate to be steel-faced must be well cleaned with 
benzine, then with caustic potash, and well rinsed 
in water. It should be placed at once in the iron 
solution and well scrubbed every five minutes, 
until a sufficient thickness of iron has been 
secured. When the face is deemed thick enough, 
wash it thoroughly in warm water, dry it quickly 
whilst rubbing with a soft brush, then coat it 
with a thin film of wax to preserve it from rust. 

Good results have been obtained from a solu- 
tion of the double salt of ammonio-sulphate of 
iron. Also from a solution of sulphate of iron 



138 THE ELECTRO-PLATERS HAND-BOOK 

and sulphate of ammonia, one part of iron sul- 
phate to five parts of water. A solution of iron 
sulphate gives good results when sal-ammoniac is 
added to the bath. It is advisable to cover the 
surface of the bath with glycerine while at 
work, and to keep it under cover when not in 
use, to prevent decomposition by action of the 
air. 

Electro-plating with Platinum. The peculiar 
character of platinum, as shown in its non-liability 
to corrosion in acid fumes and in all the simple 
acids, points to its usefulness as a protective coat- 
ing to articles of brass, copper, German silver, 
etc., used in chemists' laboratories. With 
reasonable care in conducting the process, plati- 
num can be deposited in good condition from a 
solution of the double cyanide of platinum and 
potassium in distilled water. The solution is to 
be made up as directed for making the double 
cyanide of gold and potassium, by precipitation 
from a dilute solution of chloride of platinum 
(made as directed for obtaining terchloride of 
gold) , and dissolving the precipitate in a solution 
of cyanide of potassium. As platinum solutions 
are easily decomposed by the introduction of 
other metals, and thus always liable to deposit 
the metal by simple immersion, success is 
achieved in its electro-deposition only by employ- 
ing dilute solutions and a low voltage. If a high 
voltage is used the deposit will be loose and 
spongy, presenting the appearance of black 
grains, instead of a reguline deposit. 



ZINC, TIN, IRON AND PLATINUM 139 

The solution of double cyanide of platinum 
and potassium must therefore be very dilute, and 
care must be taken to add some chloride of 
platinum at frequent intervals to neutralize the 
free cyanide, and also to replenish the solution 
with metal, since platinum anodes are not soluble 
in solutions of potassium cvanide. 

The following solution gives less trouble than 
that previously mentioned, but requires more bat- 
tery power. Take 5 fluid ounces of platinic 
chloride containing one-quarter ounce of platinum 
in 5 ounces of water, and stir it into 10 pints of 
distilled water. Take 20 drams of crystallized 
phosphate of ammonia and dissolve it in distilled 
water, then add the solution to the platinic 
chloride solution whilst stirring it with a glass 
rod. Take 100 drams of crystallized phosphate 
of soda, dissolve in distilled water and stir this 
into the mixed solution before prepared, to dis- 
solve the precipitate caused by adding the phos- 
phate of ammonia. Boil the whole in an enameled 
iron vessel until it ceases to give out the odor of 
ammonia and will slightly redden blue litmus 
paper, it is then ready for use. Work the solu- 
tion at a temperature of from 190 to 200 degrees 
Fahrenheit, using a large platinum anode and a 
current having a voltage of from 5 to 6 volts. As 
the anode does not dissolve in the solution, it is 
necessary to add some chloride of platinum occa- 
sionally to maintain the bath at its proper metal 
strength. This is best done at the close of an 
operation, adding just as much chloride as will 



140 THE ELECTRO-PLATERS HAND-BOOK 

contain enough platinum to represent that drawn 
from the bath, and stirring all well together. It 
is also advisable to add occasionally a small 
quantity of phosphate of soda to dissolve any 
platinum precipitate which may form at the bot- 
tom of the bath and to prevent it from becoming 
too acid. This solution will deposit reguline 
platinum of the usual steel-gray appearance on 
copper and brass and alloys of copper. If it is 
wished to coat with platinum such metals as iron, 
zinc, lead, tin, or alloys of these metals, they 
must first be electro -coppered, since they decom- 
pose the platinum bath and deposit the metal on 
themselves by simple immersion. 



ELECTRO-PLATING WITH ALLOYS 

Alloyed metals may be successfully deposited 
by using two or more of the metals together 
which compose the alloy to be imitated. Thus, 
various proportions of copper and zinc may be 
deposited together to form varieties of brass and 
of bronze, or copper and tin may be deposited 
together to form bronze. Copper, zinc and nickel 
may be deposited together to form German silver. 
Some interesting effects may be produced by 
depositing gold and copper, gold and silver, gold, 
silver and copper, and copper and silver together, 
from mixtures of the double cyanide solutions of 
these metals. Greater skill and care must be 
exercised to successfully deposit an alloy than 
would be employed in depositing either of the 
metals composing the alloy. Special conditions 
must be adhered to respecting the regulation of 
the current strength, strength and condition of 
the bath, and surface of the anode employed. 
Any variation from these conditions will result in 
a variation in the composition and appearance of 
the deposited alloy. The color of alloys, made 
by melting two or more metals together, depends 
very largely on the proportionate parts of the 
composition. If equal bulks of copper and of 
zinc solutions containing equal weights of the two 
metals are mixed together a mixed deposit con- 

141 



142 THE ELECTRO-PLATERS HAND-BOOK 

sisting of equal parts of the two metals copper 
and zinc will result. In practice, from such a 
solution a great variety in shades of brass may he 
obtained, depending on the temperature of the 
solution and the strength of the current. As the 
quantity of metal deposited from a solution de- 
pends greatly on its electric valency, and this 
varies with each metal, it becomes a matter of 
difficulty to always adjust the current to the com- 
position of the solution so as to deposit each 
metal in the proportion desired to obtain a given 
effect of color in the deposited alloy. 

Electro-deposition of Brass. Brass has been 
deposited from a great variety of brass solutions, 
as will be seen by reference to the annexed 
table. Among the first attempts to deposit brass 
may be mentioned that of M. de Ruolz in 1841, 
who employed a mixed solution of the double 
cyanides of copper, zinc and potassium. Cyanide 
of potassium forms an important ingredient in 
the majority of alloy solutions, but ammonia in 
some form is also necessary to keep the solutions 
in working order. 

The following conditions are to be observed in 
making up the solutions according to the propor- 
tions given in the accompanying table. Fluid 
ounces are given for liquids and avoirdupois 
ounces for the solids. When potassium car- 
bonate, carbonate of potash, is to be used, the 
copper and zinc salts are first dissolved in water 
and then precipitated as carbonates from this 
solution by adding a portion of the potassium 



ELECTRO-PLATING WITH ALLOYS 143 



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144 THE ELECTRO-PLATERS HAND-BOOK 

carbonate. Where the sign q. s. is given in the 
table, a sufficient quantity of the ammonia or 
cyanide must be added to produce the desired 
effect, ammonia being generally employed to dis- 
solve the precipitates, forming a deep blue liquid, 
and cyanide being used until the blue color has 
all disappeared. Both are employed as solvents 
to the anodes, which will not freely dissolve 
unless one or both are present in the solution. 
Even when an alloy solution is made up without 
the use of cyanide and ammonia, it is necessary 
to acid them afterwards to keep the solutions in 
working order, as the ammonia alone does not 
freely dissolve the copper of the anode, and 
cyanide alone does not dissolve the zinc oxide 
formed on the anode. The following instructions 
apply to each numbered solution in the fore- 
going table. 

1. Dissolve all the salts separately in portions 
of the water, add the ammonia in equal parts to 
the solutions of the copper and zinc salts with 
stirring, mix the copper and zinc solutions to- 
gether, then add the caustic potash solution and 
lastly the cyanide solution, stir well at frequent 
intervals during the next twelve hours, then 
allow the solution to rest a short time before 
working it. 2. Dissolve all the salts separately, 
pour enough potash solution into the solutions of 
copper and zinc to precipitate all the metal, add 
ammonia until the precipitate has been dissolved, 
iecolorizewith the cyanide, then add remainder of 
potash and water. 3. Dissolve all separately, mix 



ELECTRO-PLATING WITH ALLOYS 145 

copper, zinc and potash solutions, then add the 
nitrate of ammonia. 4. Proceed in a similar 
manner as for No. 3 solution. 5. Proceed in a 
similar manner as for No. 3 solution. 6. Dis- 
solve all the salts, add the cyanide solution to the 
others while stirring. 7. Dissolve all the salts in 
distilled water, mix together and add two ounces 
of sal-ammoniac. 8. Dissolve all the salts sepa- 
rately, then mix together. 9. Dissolve the cop- 
per and zinc salts and mix the solutions, add a 
solution of 100 parts of the carbonate of soda 
and stir well together, when the precipitate has 
subsided pour off the clear liquor, wash the pre- 
cipitate, add the remainder of the carbonate of 
soda together with the bisulphite of soda previ- 
ously dissolved in water, then add enough cyanide 
to dissolve the precipitate. 

Brass Solution. Dissolve sheet brass in nitric 
acid and use this solution instead of copper and 
zinc salts in making up the brass bath. To do 
this properly dissolve the strips of sheet brass in 
warm dilute nitric acid until the acid ceases to 
dissolve any more brass. Avoid the poisonous 
fumes as in dissolving silver, add the brass solu- 
tion to water in the proportion of one ounce of 
brass to half a gallon of water, to this add strong 
liquid ammonia until the solution assumes a clear 
deep blue color, to this add a strong solution of 
potassium cyanide until the blue color entirely 
disappears and the solution assumes the tint of 
old ale, then filter and make up with water so as 
to contain one ounce of brass in the gallon of 



146 THE ELECTRO-PLATERS HAND-BOOK 

solution. This solution will work well cold or 
hot, but should be left at rest for some hours 
after being made before it is used. 

Management of Brass Solutions. Brass solu- 
tions are not easily managed, but require constant 
attention to keep them in proper working order. 
The anodes may be of good sheet brass, or they 
may be of best rolled sheet zinc and sheets of 
copper in equal numbers. Unless the anodes 
work clean, that is, dissolve freely, the solution 
will become poor in metal and deposit an unde- 
sirable variety of brass. The zinc of the anodes 
is apt to be especially troublesome because the 
oxide of zinc formed upon them does not freely 
dissolve in the solution. To remedy this defect 
employ an excess of liquid ammonia in solution. 
If there is an excess of zinc in the solution add 
more free cyanide, and this will dissolve the cop- 
per part of the anodes. To get a solution into 
working order after it has fallen into a bad condi- 
tion, add carbonate of copper or carbonate of zinc 
dissolved in liquid ammonia, as may be required. 
If the deposit lacks brightness, dissolve a few 
grains of white arsenic in a hot solution of cyanide 
of potassium, and add this to the bath with stir- 
ring. An excess of this will give the deposit a 
steely gray appearance. The deposit of brass 
will vary with the strength of the current. A 
current of high voltage tends to deposit an excess 
of zinc, while one of too low voltage may deposit 
an excess of copper. The deposit, however, will 
be greatly affected by the volume of current 



ELECTRO-PLATING WITH ALLOYS 147 

passing, and this may be controlled by the resist- 
ance of the conductors in circuit. Thus with 
large conductors and anodes close to the article 
being plated an excess of zinc may be had, while 
with smaller conductors, good brass or an excess 
of copper. The density or the temperature of 
the solution will also affect the deposit, dense 
solutions at high temperatures being better con- 
ductors than dilute solutions at low temperatures. 
These remarks apply to all brassing solutions, 
which will generally yield results according to the 
skill and experience of the operator. 

Voltage Required for Brass-plating. Brass- 
plating solutions require a voltage of from 6 to 9 
volts, according to their composition, to deposit 
a good coat of brass. The current must be regu- 
lated according to the kind of brass desired. 

Bronzing Brass by Immersion. Brass may be 
bronzed in various colors by simple immersion in 
the solutions given in the accompanying table. 

In the preparation of No. 5, the liquid must be 
brought to a boil and then allowed to cool. In 
using No. 13, the heat of the liquid must not be 
under 180 degrees Fahrenheit. No. 6 is slow in 
action. The action of the others is for the most 
part immediate. 

Cyanide of Potassium. All directions involving 
the use of cyanide of potassium in given weights 
and proportions must be qualified by the known 
quality of the cyanide about to be used. No 
other material used by the plater is so liable to 
variations in quality. The quality is determin- 



148 THE ELECTRO-PLATERS HAND-BOOK 





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Brown and every 
shade to black. 

Brown and every 
shade to black. 

Brown and every 
shade to red. 

Brown and every 
shade to red. 

Brownish red. 

Brownish red. 

Dark brown. 

Yellow to- red. 

Orange. 

Olive-green. 

Slate. 

Blue. 

Steel-gray. 

Black. 


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ELECTRO-PLATING WITH ALLOYS 149 

able by the amount of cyanogen contained in the 
salt. Each 65 parts should contain 26 parts of 
cyanogen and 39 parts of potassium, but the best 
commercial cyanide rarely assays 98 per cent of 
cyanide of potassium, indeed it is a good sample 
which will show 95 per cent of pure cyanide. 
The impurities may consist of iron, carbon, silica, 
and the carbonate, sulphide, chloride, cyanate 
and ferrocyanide of potassium. Some of these 
are contracted during the process of manufacture. 
Carbon is added to the salt whilst in process of 
manufacture, to prevent formation of the cyanate, 
and this gives to some samples a dirty gray ap- 
pearance. White samples absorb carbonic dioxide 
from the atmosphere, with formation of the car- 
bonate and cyanate of potassium. 

Testing Cyanide of Potassium. Since so much 
depends upon the quality of the cyanide used in 
making up plating solutions, the plater should be 
prepared to test each sample before using it. 
This can be easily done by means of a burette to 
hold 1,000 grains of water, graduated in 10-grain 
divisions, and furnished with a glass stopcock. 
This instrument resembles a long glass tube and 
is held by a wood clip lined with cork, mounted 
on a stand similar to that of a filter-holder. An 
ordinary graduated glass measure will also be 
needed, and this may be employed entirely in 
making rough tests of the sample, but in this 
case a larger quantity of the sample must be used 
up in making the test, and exact accuracy can- 
not be guaranteed. 



150 THE ELECTRO-PLATERS HAND-BOOK 

The sample of cyanide to be tested must be ac- 
curately weighed in a balance showing a variation 
of one-hundredth of a grain. Either 100 grains 
of the cyanide should be weighed out, or some 
multiple of this quantity. The sample thus 
selected may be dissolved in any quantity of dis- 
tilled water, but greater accuracy is secured in 
dilute solutions containing the salt in the propor- 
tion of 100 grains in 5 fluid ounces of water. 
This solution of cyanide should be contained in a 
tall glass beaker, as it will have to be shaken by 
hand during the testing process. Then weigh out 
131 grains of pure double crystallized silver nitrate, 
dissolve in 1,000 grains of pure distilled water 
and place in the burette. Each division, or each 
10 grains of solution, will contain 1.31 grains of 
silver nitrate, and this will satisfy 1 grain of 
potassium cyanide. If 100 grains of potas- 
sium cyanide is dissolved in the solution to 
be tested, each 10 grains of the testing solution 
will satisfy 1 per cent of cyanide. Deliver the 
testing solution from the burette gradually into 
the beaker containing the cyanide solution. At 
first the silver nitrate solution will curdle as it 
touches the cyanide solution, and the curdy pre- 
cipitate will dissolve almost as soon as formed, or 
disperse on shaking the beaker. When the pre- 
cipitated silver cyanide ceases to thus quickly dis- 
solve, the beaker must be shaken or the liquid 
stirred with a glass rod until all the precipitate 
dissolves and the testing solution delivered with 
more care. Then go on delivering small quan- 



ELECTRO-PLATING WITH ALLOYS 151 

tities of the testing solution, two or three drops 
at a time, and shaking the cyanide solution 
between each delivery until the cyanide solution 
refuses to dissolve the last few drops of silver 
nitrate, and a few clots of the white precipitate 
are left undissolved. The number of divisions of 
nitrate solution thus used will show at once the 
percentage of real cyanide in the cyanide of 
potassium solution. Thus, if the 100 grains of 
potassium cyanide contain 90 grains of the active 
principle, 900 grains of the nitrate of silver solu- 
tion will have been used, and this will have been 
contained in 90 divisions of the burette. The 
sample of cyanide of potassium thus tested will 
have contained 90 per cent of real cyanide and 
10 per cent of impurities. 

Cyanide of Potassium, Testing for Free. Free 
cyanide is the cyanide of potassium contained in 
the solution over and above that needed to form 
a solution of the double salt. The presence of 
this free cyanide is absolutely necessary to the 
proper working condition of the double cyanide 
silvering and gilding solutions, since they require 
excess cyanide to dissolve the anodes and keep up 
the right working strength of -the baths. The 
quantity of free cyanide needed for this purpose 
can only be determined by experience. 



ELECTBO MECHANICAL PLATING, COLD 
GALVANIZING AND GALVANOPLASTY 

Electro-mechanical Plating. A machine for 
the purpose of plating small articles without the 
necessity of stringing or wiring them is shown in 
Figure 41. The anodes, of whatever material it 




Fig. 41. Electro-meehanical Plating Apparatus. 

is desired to plate the articles with, are shown 
suspended in the vat. The cylindrical cage in 
which the articles to be plated are placed forms 
the cathode of the outfit. The cage is rotated 
slowly in the solution at a speed of from 15 to 20 

152 



ELECTRO-MECHANICAL PLATING 



153 



revolutions per minute. Figures 42 and 43 show 
the old and the new methods of doing this class of 
work. 

It has been demonstrated by actual experience 
that a very large number of small articles can be 
successfully plated in nickel, brass, copper or zinc 
by the use of 
this outfit, thus 
avoiding the 
handling, labor 
and cost of wire 
used in string- 
ing. A partial 
list of work 
adapted for me- 
chanical plat- 
ing comprises : 
buckles, bolts, 
nuts, screws, 
nails, washers, 
trunk hard- 
ware, auto mo - 
parts, 
parts, 




Fig. 42. Old Method of Plating Small 
Articles. 



bile 

bicycle 

sewing machine parts, typewriter -parts, saddlery 

hardware, screw eyes, pulley wheels, musical 

instrument parts, hinges, general hardware. 

Cold Galvanizing. It has been demonstrated 
that in the application of zinc by the electrolytic 
cold process a much smaller amount of protect- 
ing metal to the square foot is required than is 
necessary in hot or dip galvanizing. At the same 



154 THE ELECTRO-PLATERS HAND-BOOK 



time the protective quality of the electrically 
deposited zinc is greater, and the deposit more 
uniform than can be obtained where hot metal is 
used. 

Tempered articles, coil springs, automobile and 
bicycle hardware, and like goods of comparatively 

small section or 
high temper, 
sometimes lose 
a part of their 
tensile strength 
or temper when 
subjected to the 
heat of the mol- 
ten bath, which 
is about • 774 
degrees Fah- 
renheit. This 
is a disadvant- 
age not present 
in the cold proc- 
ess. The fol- 
lowing articles 
have been suc- 
cessfully treat- 
ed by the 
electrolytic 
process : lag 
screws, bolts, 
nuts, washers, rods, angle irons, plumbers' 
hardware, sheet iron, hose couplers, spanners, 
wire clips, clamps, hinges, steel laths, hoop 




Pig. 43. New Method of Plating Small 
Articles. 



ELECTRO-MECHANICAL PLATING 155 

iron, axles, wrenches, die stocks, braces and 
bars. 

Galvanoplasty. This name was originally given 
to an electro-reproduction of printing type in 
copper, but has since been extended to similar 
reproductions of chased, engraved and rough 
surfaces, and also the replication in electro- 
deposited copper of images and statues. The 
process may be briefly described as follows: 
First, a mould of some plastic substance is taken 
of the subject to be copied, the surface of the 
mould is coated with a conductive film, and this 
film is connected to the wires employed to sus- 
pend the mould in the depositing solution. 
Second, the mould is suspended in a solution of 
copper sulphate, connected by suitable wires with 
the negative pole of an electric battery or 
dynamo, a plate of copper to form an anode is 
connected to the positive pole of the electric 
generator and suspended in the solution opposite 
to the mould, and an electric current is passed 
between them until the mould is covered with a 
strong coating of copper. Third, when the coat 
of copper on the mould is deemed to be thick 
enough for the purpose required, it is removed 
from the mould, well washed to free it from cop- 
per salts, allowed to dry, then strengthened by 
the application of solder or type metal to the 
back and mounted on a suitable block or support. 

To ensure success in this process it is advisable 
to follow certain instructions relating to details 
dictated by the experience of others. These 



156 THE ELECTRO-PLATERS HAND-BOOK 



relate mainly to the choice and manner of work- 
ing the moulding material, the arrangement of 
conducting wires, the choice and management of 
the depositing solution and the regulation of 
electric current employed in depositing the 
copper. 

Moulds for galyanoplasty have been made of 
various materials, such as gutta-percha, bees-wax, 
sealing-wax, shoemaker's wax, paraffine, stearine, 

marine glue, 
sulphur, plas- 
ter of Paris, 
gelatine, and 
fusible metal. 
Gutta-percha 
may be em- 
ployed as a 
mould to take 
the impression 
of a flat en- 
graved surface, 
coin, medal, or similar object capable of bear- 
ing pressure without injury. The gutta-percha 
is made soft in scalding hot water, rolled in 
the hands under cool water to form a smooth 
ball, pressed on the oiled coin and worked 
all over it with the ringers, then put under 
pressure until it is cold and hard. Both sides of 
the medal or coin must be thus copied on sepa- 
rate moulds. Bees-wax may be usad in a similar 
manner, but it is generally employed in a molten 
condition, when it is poured over the object to be 



^' ' — — i 

a 

a JJ — — TIT'S 



Fig. 44. Double Cell, Double Liquid 
Battery Plating Outfit. 



ELECTRO-MECHANICAL PLATING 157 

copied whilst this is held in a suitable metal tray. 
The wax should be completely melted over a hot 
water bath, then allowed to partially cool before 
pouring it in the moulding tray. An ounce of 
dry white lead stirred well into each pound of 
molten wax is said to improve the mould. Bees- 
wax has been extensively used for electrotypes of 
printers' forms and engravings. Paraffine, stear- 
ine and marine glue have been used in a similar 
manner, but are not recommended. Sealing-wax, 



Fig. 45. Double Cell, Single Liquid Battery Plating Outfit. 

shoemaker's wax and sulphur have been used by 
amateurs and experimenters, with varying success, 
in copying coins and medals. Plaster of Paris 
has been largely employed as a moulding material 
in copying images, statues, busts, and other 
works of art. The very best plaster must be had 
for this purpose. The work to be copied must be 
first oiled all over. The plaster is then mixed 
with water to the consistence of cream and poured 
at once over the object to be copied, and allowed 



158 THE ELECTRO-PLATERS HAND-BOOK 

to set hard before it is removed. Images, statues 
and similar rounded objects must be copied in 
two or more moulds separately. When such 
objects are much undercut, copies must be taken 
of them in printers' composition, a mixture of 
glue and molasses, and this elastic material em- 
ployed as a mould for a copy in bees-wax. Gela- 
tine is used in taking copies of finely-engraved 
plates and other works of art in which very fine 
lines only are employed. As this substance is 
readily soluble in water, a solution of it is em- 
ployed, and this is poured on the object to be 
copied, then allowed to set hard by drying before 
taking off the film. As this film is liable to 
swelling and consequent distortion in the deposit- 
ing solution, it. is necessary to so treat it as to 
render it insoluble in water. This is attained by 
mixing bichromate of potash solution, or a solu- 
tion of tannic acid with the gelatine before 
moulding, and exposing the mould to strong sun- 
light for several hours. Gelatine and also glue 
are rendered insoluble in water by this process. 

As the moulding materials employed in making 
galvanoplastic moulds are either non-conductors 
or bad conductors of electricity, it is necessary to 
coat the surface to be copied with some conduct- 
ing substance to serve as a bridge for the coating 
of copper. Moulds of gutta-percha, bees-wax, 
resinous substances and plaster of Paris are coated 
with black lead applied with a soft brush. Only 
the finest and best powdered black lead must be 
employed, and this is carefully brushed whilst 



ELECTRO-MECHANICAL PLATING 



159 



dry into every crevice of the surface to be copied 
until every part has been covered with a film of 
the powder. Fine bronze powder mixed with 
two-thirds black lead forms a superior conducting 
film. Moulds of plaster of Paris must be previ- 
ously well dried, coated with warm stearine or 
paraffine, baked in an oven, again well saturated 
with hot melted stearine or paraffine, then baked 
hard to prevent the plaster from absorbing the 
coppering solu- 
tion. Moulds 
composed of 
gelatine, glue, 
and elastic or 
printers' com- 
position, must 
be first rendered 
insoluble. This 
is done by mix- 
ing two parts 
of tannic acid 
with the sol u- 
tion to each 100 parts of the dry glue or gelatine 
employed, or by soaking the mould in a 10 per 
cent solution of bichromate of potash, then ex- 
posing it to strong sunlight for some hours. 
Moulds may be metallized by one of the following 
processes: Wet the surface with a strong solu- 
tion of nitrate of silver, place it on a porcelain 
plate under a bell glass and expose it to the 
action of sulphureted hydrogen, hydrogen gas, 
or the vapor of phosphorus dissolved in carbon 




Fig. 46. Amateur Plating Outfit. 



160 THE ELECTRO-PLATERS HAND-BOOK 



bisulphide. Wash the surface alternately at 
intervals of five minutes with a solution of one 
part silver nitrate in four parts of distilled water, 
and a solution of one part protosulphate of iron 
in three parts of distilled water. When the sur- 
face has a whitish-gray tint, rinse in clean water, 
immerse in the plating solution and connect at 
once to the battery. This preparation takes a 
film of copper rapidly. Wash the surfaces with 
iodized collodion, followed by a solution of silver 

nitrate, and af- 
ter exposure to 
light a solution 
of protosul- 
phate of iron 
acidulated with 
nitric acid. 

The conduct- 
ing surface of 
the metallized 
mould mur,t be 
connected to 
the wire leading to the battery or dynamo. 
One, two, or more fine copper wires have their 
ends inserted in the edge of the mould, and 
the black lead or other conducting medium is 
carefully brushed around the ends of the wires 
to form a starting-point for the deposit. In 
copying statues or busts, a perfect network of 
such fine wires are formed, with their ends stick- 
ing into every remote part of the mould. These 
wires are then twisted around a main line wire to 




Fig. 47. Silver and Gold Plating Outfit. 



ELECTRO-MECHANICAL PLATING 161 

form the main conductor leading to the negative 
pole. Forms of type and similar large surfaces 
are connected by copper straps leading from the 
frame of the mould. 

After connecting the mould in the plating solu- 
tion with the dynamo, a spot of electro-deposited 
copper will appear on the surface of the mould 
connected to the end of the conducting wire, and 
this spot will spread all over the surface of the 
mould with more or less rapidity, depending on 
the condition of the metallic coat and that of the 
arrangements. A small mould may be coated in 
the course of a few minutes or within an hour, 
and yet have a good deposit. The rate of deposit 
is affected by the density and temperature of the 
solution, the relative size and nearness of the 
anode and mould and the strength of the current, 
The character of the deposit is also affected in a 
similar manner. A dense solution, one contain- 
ing too much copper and too little water, a low 
temperature, low battery power, anodes too small, 
or too great a distance between the moulds and 
anodes, may result in a slowly formed and b little 
deposit. A weak solution, one poor in metal, a 
high temperature, too high battery power, anodes 
too large, or moulds and anodes too close to- 
gether, may cause a quickly deposited coat of a 
loose and porous structure. When the solution is 
too dense, the thickness of the deposit may be 
unequal, and Bark streaks appear on it, but this 
same =defect may be caused by density in the 
lower part of the solution only, due to want of 



162 THE ELECTRO-PLATERS HAND-BOOK 

stirring. The solution should be stirred every 
evening or at least once a day. The anodes and 
the zinc elements should be slightly larger than 
the surface to be coated. The temperature 
should be as near 60 degrees Fahrenheit as pos- 
sible, but 5 degrees lower may be permitted. A 
voltage of from one to two volts is enough to 
deposit copper in good condition. Higher vol- 




Fig. 48. Steam Generator Connected to Dipping and Scouring 

Kettles. 



tages may be required to push the desired volume 
of current through resistances, but a reduction of 
resistance is preferable to an increase of voltage. 
Much can be done in regulating the rate and 
character of the deposit by reducing the resist- 
ance in the outer circuit, by enlarging the anodes, 
using larger conducting wires and placing the 
moulds nearer the anodes. The resistance may 
also be increased, if desired, by the opposite 



ELECTRO-MECHANICAL PLATING 163 

arrangement, or by the use of a resistance board in 
the circuit. Water will be required occasionally 




to make up for loss by evaporation, but no other 
alteration should be made in a good plating solution. 



164 THE ELECTRO-PLATERS HAND-BOOK 

When a sufficiently thick si] ell of copper has 
been obtained on the mould it should be taken 
out of the solution, rinsed in tepid water, and the 
two carefully separated to avoid any buckling of 
the shell. This should then be washed in hot 
water to free it from salts, then dried. When 
dry, lay it face downward on a flat surface, brush 
the back with soldering fluid, sprinkle it with 
grain soft solder, and place it on a hot plate to 
melt the solder, then brush the molten solder all 
over the back. This will give stiffness to the cop- 
per shell. The edges may now be trimmed 'with 
sharp shears and the electros mounted, The 
obverse and reverse of medals and coins may have 
their backs thickened and soldered together, or 
be soldered to flat discs of metal furnished with 
loops. They may then be silver-plated or gilded 



USEFUL INFORMATION 

Burnishing. If a very highly polished surface 
is required on spoons, forks, knives and heavily 
plated table ware, they are given to the bur- 
nisher, after they have been scratch-brushed, 
instead of to the polisher and finisher. In large 
establishments the work of burnishing is usually 
done by skilled female operators who have become 
skillful in the use of the tools by long practice. 

The operation of burnishing is performed by 
means of steel tools. These tools are pressed on 
the surface of the plated article and rubbed to 
and fro until a bright, mirror-like surface has 
been produced. 

The plated articles, having been scratch-brushed 
and dried in sawdust, are then taken in hand to 
be burnished. The work is first prepared by 
scouring the surface with very fine silver sand 
applied on a soft flannel pad dipped in warm 
soapy water. This is done to level down any 
roughness left from the scratch- brush, and so 
secure a uniform surface, but the amateur can 
effect a similar condition by first going over the 
^surface on his polishing lathe and then brushing 
it with a soft brush dipped in warm soapy water. 
The work is then well rinsed in warm water and 
dried by rubbing with soft linen rags. The next 
operation is grounding. This is done with bur- 

165 



166 THE ELECTRO-PLATERS HAND-BOOK 

nishers having a long thin edge. A set of "bur- 
nishers of different sizes and shapes to suit the 
different surfaces to be burnished are shown in 
Figure 25. 

These tools are mounted in wooden handles 
about four inches in length. The tool is held in 
the right hand with the handle resting on the 
back of the little finger near the first knuckle, 
the next three fingers on the upper part of the 
handle, and the thumb on the top to apply pres- 
sure. The work is placed on a pad of linen rag 
on a bench or table of convenient height. A lu- 
bricating liquid having been made of soap shav- 
ings and warm water, the burnisher is dipped in 
the suds and applied to the surface of the plated 
article in a slanting direction with moderate 
pressure. The strokes of the burnisher are so 
directed that each succeeding stroke shall slightly 
overlap that of its predecessor. The strokes 
must be all in one direction, and the surface thus 
gone over until all has been grounded. This 
will leave an imperfectly burnished surface. The 
whole is then gone over with a thicker steel bur- 
nisher in a similar manner to erase the marks left 
by the grounding tool. The burnisher must be 
kept well lubricated with soap-suds during the 
whole process, or it will heat, drag on the surface 
and strip the coat. It must also be wiped fre- 
quently to remove the dirty suds, and frequently 
polished on a piece of buff leather fixed on a slab 
of wood, such as a razor strop, hone or oilstone, 
charged with jeweler's rouge. Fresh suds must 



USEFUL INFORMATION 167 

be made up for each day's work, and the burnish- 
ers must be kept free from the least trace of rust 
by frequent examination and polishing. Plated 
articles made of white metal, pewter, lead, and 
similar soft metals, will not stand burnishing, 
and only very moderate pressure may be applied 
to those made of copper or of soft brass. Thin 
deposits should be very lightly burnished, or not 
burnished at all if very thin. 

A complete set of burnishing tools is shown in 
Figure 25. 

Quickening Solutions. A plater is sometimes 
called upon to give a very thin and cheap coating 
of silver or gold upon articles which, from their 
nature and the metal of which they are com- 
posed, cannot be polished and prepared for plat- 
ing in the ordinary way, such as photograph 
frames in thin, perforated designs, cast from a 
mixture of tin, lead and antimony or zinc, and 
various other designs. These goods are generally 
brought to the plater as soon as cast and must be 
plated immediately for a very slight cost. 

The goods are strung on wires, dipped into hot 
water, then into a hot quickening solution, com- 
posed of a strong solution of bichloride of mercury 
and sal-ammoniac, which leaves a very thin film 
of mercury on the article. It is then transferred 
to a silver solution low in silver and strong in 
cyanide, kept in it a moment, rinsed in hot water 
and dried and lacquered immediately. The whole 
operation must be performed rapidly and the 
work kept constantly in motion while in the solu- 



168 THE ELECTRO-PLATERS HAND-BOOK 

tions. The entire process ought not to occupy 
oyer two minutes. Cheapness and speed are the 
sole requirements. When doing such jobs the 
plater must insist that the work be lacquered 
immediately. It will discolor if allowed to stand 
three or four hours without lacquer. 

Another quickening solution frequently used 
on work compos, d of one of the many so-called 
German silver alloys, consists of a weak solution 
of potassium mercury cyanide in water. A weak 
solution of acidulated nitrate of mercury is also 
frequently used on work of this class. 

These solutions are often useful in replating old 
work which has a tendency to refuse to plate in 
spots that have been badly corroded. There is 
no special rule to be observed in regard to 
strength, the main object is simply to coat with 
mercury spots that will not plate without it and 
the less mercury employed to amalgamate the 
surface the better for the work. Such solutions 
should be employed just before the work is put 
into the plating bath, and they should always be 
followed by hot rinsing and the work never 
allowed to dry. 

Always keep the quickening solutions for the 
various metals separate from each other. Cov- 
ered ten or twenty gallon stone jars are generally 
used to hold such solutions. 

Stopping off Deposits. It is sometimes advisable 
to ornament articles with various shades of gold 
in different parts, or with patches of gold, and 
silver, and copper. This is done by stopping off 



USEFUL INFORMATION 169 

the deposit of gold or silver from the parts to be 
left uncovered with a suitable non-conducting 
varnish. After the gold or silver has been de- 
posited on the part to be ornamented, the varnish 
is dissolved off with warm spirits of wine (grain 
alcohol). The following is a list of varnishes 
suitable for the purpose. Yellow stopping-off 
varnish: Best copal varnish colored with 
chromate of lead. This will protect metals in 
cold solutions only. Blue stopping-off varnish: 
Best copal varnish colored with ultramarine. 
Eed stopping-off varnish : Best quick-drying 
copal varnish colored with rouge. These var- 
nishes will dry in about three or four hours, and 
will resist hot cyanide solutions. 

Points to Remember. An area equal to one 
square inch is required to carry 1,000 amperes. 
A copper rod 1 inch by 1 inch, or a strip of cop- 
per 4 inches by a quarter inch or 2 inches by a 
half inch will fill this requirement. If round 
wire is used an area equal to one square inch 
must be employed, or a conductor about 1^ inches 
in diameter. 

The above specifications apply only to installa- 
tions where the distance from the dynamo to the 
tank, measuring along the entire length of the 
conducting wire, is not more than 40 feet. For 
distances greater than 40 feet the size of the con- 
ductor should be increased as the distance is in- 
creased. Double the size of conductor is needed 
for a line connection of 80 feet, while 50 per 
cent increase in the size of the wire is required 



170 THE ELECTRO-PLATERS HAND-BOOK 

if the distance is increased 50 per cent over 40 
feet. 

In arranging branch wires from the main line 
to the tank it is necessary that the wires be large 
enough to carry, without heating, enough 
amperage to plate the full load ©f the tank. 
The capacity of the tank in square feet of work 
surface can be readily determined, then with a 
knowledge of the amperage required to plate a 
square foot of surface of the various metals the 
total number of amperes needed for a full tank 
and the size of the wire best adapted to carry the 
current can be readily determined. 

For the convenience of platers, tables are given 
showing the number of amperes required to de- 
posit a square foot of surface of each of the vari- 
ous metals, also weight and carrying capacity of 
the different sizes of copper wire and the loss in 
volts. 



Amperes Required to 

Plate One Square Foot 

of Surface. 


Carrying Capacity of Insulated 
Copper Wire. 


Metal. 


Amperes. 


Size. 


Amperes. 


Nickel . . . 
Brass. . . . 
Bronze . . . 
Copper* . . 
Silver .... 

Zinc 

Gold 


4 

6 or 8 
6 or 8 
6 or 8 
2 

U 

10 


No. 3 B. & S. G. 
No. B. & S. G. 
No. 0000 B. & S. G. 
\ inch 

f " 
t " 

7 " 
8 
1 


50 
100 
180 - 
225 
350 
500 
650 
750 
1000 



*Acid copper solutions require 10 to 12 amperes. 



USEFUL INFORMATION 



171 



Voltage for Solutions. All platers should 
understand that different voltages are required 
to operate successfully different kinds of solu- 
tions, and that when a sufficient voltage is to be- 

Weight, Carrying Capacity and Loss in Volts of 
Copper Wire. 











Safe 


Loss in 






Pounds 


Weight 


Carrying 


Volts per 




Diame- 


per 10j0 


per 1000 
Feet of 


Capacity 


Ampere 


B. &S. 


ter in 


Feet of 


in 


per 100 


Gauge. 


Inches. 


Bare 


Insulated 


Amperes 


Feet of 






Wire. 


Wire. 


of Bare 
Wire. 


Double 
Line. 


0000 


.46 


610.5 


825 


312. 


.0098 


000 


.409 


508.5 


610 


262. 


.0123 


00 


.364 


402.8 


458 


220. 


.0155 





.324 


319.6 


385 


185. 


.0195 


1 


.289 


253.4 


308 


156. 


.0247 


2 


.257 


201.0 


249 


131. 


.0311 


3 


.229 


159.3 


201 


110. 


.0392 


4 


.204 


126.4 


163 


92.3 


.0495 


5 


.181 


100.2 


133 


77.6 


.0624 


6 


.162 


79.46 


109 


65.2 


.0787 


7 


.144 


63.01 


90 


54.8 


.0992 


8 


.128 


49.98 


74 


46.1 


.125 


9 


.114 


39.64 


62 


38.7 


.158 


10 


.101 


31.43 


52 


32.5 


.199 


11 


.090 


24.93 


43 


27.3 


.251 


12 


.080 


19.77 


36 


23. 


.316 


13 


.071 


15.68 


30 


19.3 


.399 


14 


.064 


12.43 


25 


16.2 


.503 


15 


.057 


9.86 


21 


13.6 


.634 


16 


.050 


7.82 


18 


. 11.5 


.799 


17 


.045 


6.20 


15 


9.6 


1.088 


18 


.040 


4.92 


13 


8.1 


1.271 



generated for a solution of the highest resistance, 
and at the same time utilized in low resistance 
solutions, the tank nearest the dynamo, with the 
customary method, receives the most current, 
and a tendency to burn and blacken is noticed to 



172 THE ELECTRO-PLATERS HAND-BOOK 

a marked degree. When metals such as silver 
and copper are to be deposited in connection with 
such metals as nickel and brass, a higher electro- 
motive force is required, and considerable drop in 
voltage is demanded in the lower resistance solu- 
tions so as not to blacken the work. 

Lacquering. The exercise of a little care in 
preparing articles for lacquering will add greatly 
to the finished product, insure satisfactory re- 
sults, and cause the lacquer to become much 
more effective. In nearly all instances where 
trouble occurs the cause is directly traceable to 
either inexperience, imperfect cleaning, or care- 
lessness in application. It is therefore necessary 
to observe the fundamental rules so familiar to all 
experienced users of lacquers. First, if the 
lacquer is too thin it will show iridescent colors. 
Second, if the lacquer is too heavy it will show a 
drip when employed for dipping. Third, if the 
lacquered articles show a white, milky cloud, it 
is always due to moisture or grease. If the direc- 
tions and suggestions given here are carefully fol- 
lowed, perfectly satisfactory results will be 
obtained. 

Dip Lacquers. Use a tin-lined wooden tank for 
holding the lacquer, or chemically enameled iron 
tanks. For holding dip lacquers use stoneware, 
glass, or enameled iron rectangular or cylindrical 
tanks. When not in use, cover with wood or 
sheet galvanized covers. Have the work as clean 
as for plating. Arrange the goods so the lacquer 
will run off properly. Allow them to drip over 



USEFUL INFORMATION 



173 



the drip tank until the lacquer stops flowing. 
Dry in a temperature of 100 degrees Fahrenheit, 
if possible, using a thermometer. Dip lacquers 
will dry in the air, but baking improves the fin- 
ish. Use the lacquer as shipped until it shows a 
drip or nipple in drying. Thin only with thinner 
of same grade. 

Brush Lacquers. Brush lacquers cannot be 
used as thin as dip lacquers. Use as thin as pos- 




Fig. 50. Lacquering Plant. 



sible without showing rainbow colors. Give a 
flowing coat with a soft lacquer brush. A stiff 
brush will require a thicker lacquer, and will 
cause foaming or small air bubbles. All dip 
lacquers should be dried by heat in a temperature 
of about 100 degrees Fahrenheit. Thermometers 
for this work should always be used. Rainbow 
colors are in most cases caused by the lacquer 



174 THE ELECTRO-PLATERS HAND-BOOK 

being too thin or by carelessness in removing the 
crocus composition or rouge from the work. 
Grease is very injurious to lacquer. 

Antidotes to Poisoning. To preserve the health 
of the workmen in the shop should be one of the 
chief considerations of the plater, since more and 
better work is done by healthy than by unhealthy 
workmen. An abundance of fresh air should be 
insisted on in all weathers, even if more clothing 
has to be worn. This can be insured without 
exposing any one to draughts, by the exercise of 
proper care in the ventilation. A want of pure 
air to mix with the poisonous fumes inseparable 
from a plating shop, must result in poisoning of 
the blood, since that passes through lungs 
charged with the poisonous air. For the same 
reason extra care should be taken to carry away 
from the workman any fumes raised in chemical 
operations, such as those from the preparation of 
solutions and from pickling operations. If the 
workmen must handle very frequently or con- 
tinuously articles in contact with cyanide of 
potassium or solutions of this poison, the hands 
should be protected with rubber gloves, since 
cyanogen is readily absorbed by the skin, causing 
ill health. This absorption of cyanogen causes 
painful sores on the hands. These are best 
treated by dipping the sore into dilute sulphuric 
acid in 10 parts of water, freshly mixed, and 
enduring the consequent pain as long as possible. 
Then well wash the sore in warm soapy water and 
bind it up in a rag wet with soap-suds. 



TABLE OF CONTENTS 

Electrical Rules and Formulas. 

Electricity — Electromotive force — The volt 
— The ampere — The ohm — Ohm's Law — 
Single conductor closed circuits. Page. . . . 7-11 

Batteries. 

Arrangement of battery cells in series, paral- 
lels and parallel-series. Page 12-17 

Electro-plating with Batteries. 

Single liquid battery — Double liquid battery 
— Construction of batteries — Amalgamation 
of zinc. Page 18-22 

Electro-plating Dynamos. 

Principle of a dynamo — Selecting a plating 
dynamo — Choice of a dynamo — Plating dy- 
namo — Compound versus shunt wound dy- 
namos — Compound wound plating dynamo 
^Speed of plating dynamos — Efficiency of 
dynamos. Page 23-34 

Electro-platers Materials. 

Plating vats — Tanks — Dipping baskets — 
Scouring brushes — Scratch brushes — Dust 
brushes — Polishing wheels — Directions for 
using polishing wheels — Balancing of polish- 
„ ing wheels — Polishing lathes — Polishing ma- 
terials — Lime — Rouge — Crocus — Pumice 
stone — Speed of wheels — Wheel truing de- 
vice — Wheel cleaning machines — Belt straps 
— Belt strapping machine — Burnishing tools 
— Hydrometers — Thermometers — Use of rhe- 
175 



176 TABLE OF CONTENTS 

Electro-platers Materials — Continued. 

ostats — Voltmeters — Ammeter — Time dial — 
Steam generator — Rubber gloves — -Finger 
cots — Wooden shoes — Rubber aprons — Felt 
bags — Glue pot and brush — Rod and wire 
connectors. Page 35-69 

Electro-deposition of Metals. 

Suitable depositing solutions — Metals easily 
deposited — Metals of low cost — Metals not 
easily deposited — Deposition by simple im- 
mersion — Rate of deposit of metal. Page . . 70-74 

Cleaning the Work. 

Cleaning cast iron — Cleaning wrought iron 
or steel — Cleaning copper, brass and Ger- 
man silver — Cleaning old articles — Cleaning 
work by hand — Polishing jewelry. Page.. 75-85 

Dips and Dipping. 

Potash and cyanide dips — Iron pickle — 
Bright dip for iron — Copper, brass and bronze 
pickle — Bright dip for copper or brass — 
Cyanide dip for brass — Pickle for German 
silver. Page 86-88 

Stripping. 

Cleaning zinc — Cleaning white metal and 
pewter — Cleaning silver and gold — Cleaning 
off corrosion and rust. Page. . . . 89-94 

Electro-plating with Nickel. 

Voltage required to deposit nickel — Finish- 
ing nickel plating — Care of nickel baths — 
Nickel-plating cycle fittings — Re-plating old 
cycle fittings — Working nickel solution — 
Double salts of nickel — Rate of nickel depo- 
sition — Black nickel-plating — Boracic acid. 
Page 95-102 



TABLE OF CONTENTS 177 

Electro-plating with Silver. 

Finishing of silver-plated articles — Polish- 
ing silver plate and silver — Silver-plating so- 
lutions — Character of silver deposit — Thick- 
ness of silver deposits. — Rate of silver depos- 
its — Bright silver-plating — Nitrate of silver 
— Cyanide of silver — Double cyanide of sil- 
ver and potassium. Page 103-120 

Electro-plating with Gold. 

Cyanide of gold — Double cyanide of gold and 
potassium — Characteristics of gold deposits 
— Strength of gilding bath — Polishing and 
finishing electro-gilt articles — Assaying gold 
and silver solutions. Page 121-128 

Electro-plating with Copper. 

Alkaline solutions of copper — Cyanide of cop- 
per solution — Alkaline copper solution — 
Working alkaline copper solutions — Rate and 
thickness of copper deposits. Page 129-133 

Electro-plating with Zinc, Tin, Iron and 
Platinum. 
Electro-plating with zinc — Zinc-plating solu- 
tion — Tin-plating — Electro-plating with tin 
— Electro-plating with iron — Electro-plating 
with platinum. Page 134-140 

Electro-plating with Alloys. 

Electro-deposition of brass — Alloy-plating 
solutions — Brass solutions — Management of 
brass solutions — Voltage required for brass- 
plating — Bronzing brass by simple immer- 
sion — Cyanide of potassium — Testing cyan- 
ide of potassium — Testing for free cyanide of 
potassium. Page 141-151 

Electro-mechanical Plating, Cold Galvaniz- 
ing AND GALVANOPLASTY. 

Electro - mechanical plating — Electro - me - 
chanical plating apparatus — Old method of 



178 TABLE OF CONTENTS 

Electro-mechanical Plating, Cold Galvaniz- 
ing and Galvanoplasty — Continued. 
plating small articles — New method of plat- 
ing small articles — Cold galvanizing — Gal- 
vanoplasty. Page 152-104 

Useful Information. 

Burnishing — Quickening solutions — Strip- 
ping off deposits — Points to remember — 
Amperes required to plate one square foot 
of surface — Carrying capacity of insulated 
copper wire — Voltage for solutions — Weight, 
carrying capacity and loss in volts of copper 
wire — Lacquering — Dip lacquers — Brush 
lacquers — Antidotes to poisoning. Page.. 165-174 



306 90 



THE MOST IMPORTANT BOOK ON ELECTRICAL CONSTRUCTION 

WORK FOR ELECTRICAL WORKERS EVER PUBLISHED. 

NEW 1904 EDITION. 

MO DERN WIRING 
DIAGRAMS AND DESCRIPTIONS 

A Hand Book of practical diagrams and 
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MODERN ELECTRICAL 
n^v^ CONSTRUCTION 



By HORSTMANN and TOUSLEY 



TTThIS book treats almost entirely of practical electrical 
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MODERN LOCOMOTIVE 
ENGINEERING 



20th Century 
Edition 



By C. F. SWINGLE, M. E« 




THE most modern and practical work published, treating upon the 
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The Latest, Best and Most Complete Book on Engineering and Electricity 
published. Written by practical Engineers and Electricians in a way 
that you can understand it. UP-TO-DATE 1904 EDITION. 

m s 20th Century Hand Book 

■ F^OR- 

Engineers and Electricians 

A COMPENDIUM 
of useful knowl- 
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By C. F. SWINGLE, M.E. 

Formerly Chief Engineer of the Pullman Car Works. L,ate Chief Eugineer 
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ELECTRICAL DIVISION 

The electrical part of this valuable volume was written by a practical 
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ery. No better or more complete electrical part of a steam engineer's 
book was ever written for the man in the engine room of an electric 
lighting plant. 

SWINGLE'S 20th CENTURY HAND BOOK 

FOR. ENGINEERS AND ELECTRICIANS 

Over 300 illustrations; handsomely bound in full leather pocket <£ft Cft 
book style; size 5 x <o% x 1 inch thick. PRICE NET . . . . $£iUU 

Sold by booksellers generally or sent postpaid to any 
address Upon receipt of price. 

FREDERICK J. DRAKE G COMPANY 

Publishers of Self-Educational Books for Mechanics 
2II-2I3 East Madison Street CHICAGO, U.S.A. 



A BOOK EVERY ENGINEER AND ELECTRICIAN 
SHOULD HAVE IN HIS POCKET. A COMPLETE 
ELECTRICAL REFERENCE LIBRARY IN ITSELF 

NEW EDITION 
15he Handy Vest-Pocket 

ELECTRICAL 
DICTIONARY 

BY WM. L. WEBER, M.E. 
ILLUSTRATED 




CONTAINS upwards of 4,800 words, 
terms and phrases employed in the 
electrical profession, with 'their 
definitions given in the most concise, 
lucid and comprehensive manner. 

The practical business advantage 
and the educational benefit derived 
from the ability to at once understand 
the meaning of some term involving 
the description, action or functions of 
a machine or apparatus, or the physi- 
cal nature and cause of certain phe- 
nomena, cannot be overestimated, and 
will not be, by the thoughtful assidu- 
ous and ambitious electrician, because 
he knows that a thorough understand- 
ing, on the spot, and in the presence 
of any phenomena, effected by the aid 
of his little vest-pocket book of refer- 
ence, is far more valuable and lasting 
in its impression upon the mind, than 
any memorandum which he might 
make at the time, with a view to the 
future consultation of some volumin- 
otis standard textbook, and which is 
more frequently neglected orf orgotten 
than done. 

The book is of convenient size for 
carrying in the vest pocket, being only 
2% inches by hV 2 inches, and M inch 
thick; 224 pages, illustrated, and 
bound in two different styles: 

New Edition. Cloth, Red Edges, Indexed . . 25c 
New Edition. Full Leather, Gold Edges, Indexed, 50c 

Sold by booksellers generally or sent postpaid to any address upo* receipt 
of price. 

FREDERICK J. DRAKE & COMPANY 

Publishers of Self-Educational Books for Mechanics 
an-213 E. MADISON ST. CHICAGO, U.S. A 




Easy Electrical Experiments 
and How to Make Them 

By L. P. DICKINSON 

This is the very latest and most 
valuable work on Electricity for the 
amateur or practical Electrician pub- 
lished. It gives in a simple and 
easily understood language every 
thing you should know about Gal- 
vanometers, Batteries, Magnets, In- 
duction, Coils, Motors, Voltmeters, 
Dynamos, Storage Batteries, Simple 
and Practical Telephones, Telegraph 
Instruments, Rheostat, Condensers, Electrophorous, 
Resistance, Electro Plating, Electric Toy Making, etc. 
The book is an elementary hand book of lessons, 
experiments and inventions. It is a hand book for 
beginners, though it includes, as well, examples for 
the advanced students. The author stands second to 
none in the scientific world, and this exhaustive work 
will be found an invaluable assistant to either the 
Student or mechanic. 

Illustrated with hundreds of fine drawings; printed 
on a superior quality of paper. 

J2mo Cloth. Price, $1.25. 

Sent postpaid to any address upon receipt of price. 

FREDERICK J. DRAKE <a CO, 

PUBLISHERS 

S5^^ Chicago 



JUST THE BOOK FOTS BEGINNERS AND ELECTRICAL WORKERS 

WHOSE OPPORTUNITIES FOR GAINING INFORMATION ON 

THE BRANCHES OF ELECTRICITY HAVE BEEN LIMITED 



ELECTRICITY 

Made Simple 

By CLARK CARYL HASKINS 

A BOOK DEVOID OF 

TECHNICALITIEvS 

SIMPLE, PLAIN AND 

UNDERSTANDABLE 

There are many elementary books about 
electricity upon the market but this is 
the first one presenting the matter in 
such shape that the layman may under- 
stand it, and at the same time, not writ- 
ten in a childish manner. 

FOR ENGINEERS, DYNAMO MEN, 
FIREMEN, LINEMEN, WIREMEN AND 
LEARNERS. FOR STUDY OR 
REFERENCE. 

This little work is not intended for the instruction of experts, nor as 
a guide for professors. The author has endeavored throughout the book 
to bring the matter down to the level of those whose opportunities for 
gaining information on the branches treated have been limited. 

Four chapters are devoted to Static Electricity ; three each to Chemi- 
3al Batteries and Light and Power ; two each to Terrestrial Magnetism 
and Electro-Magnetism ; one each to Atmospheric Electricity ; Lightning 
Rods; Electro -Chemistry; Applied Electro -Magnetism; Force, Work 
and Energy; Practical Application of Ohm's Law; also a chapter upon 
Methods of Developing Electricity, other than Chemical. 

The large number of examples that are given to illustrate the practi- 
cal application of elementary principles is gaining for it a reputation as 
a text book for schools and colleges. 

In reviewing this book an eminent electrician says of it : 

"All that 999 men out of 100U want to know can be imparted in plain 
xanguage and arithmetic. I therefore think that such a book as yours 
is the kind that does the greatest good to the greatest number." 

I2mo, Cloth, 233 Pages, 108 Illustrations tf* f|ft 
PRICE JSTet #>1*UU 

For Sale by booksellers generally or sent postpaid to any 
address upon receipt of price, 

FREDERICK J. DRAKE & CO., Publishers 
21 1 -313 E. Madison Street, CHICAGO, U.S.A. 




THE AUTOMOBILE HAND-BOOK 



A WORK of practical information for the use of Owners, Operators and 
•**■ Automobile Mechanics, giving full and concise information on all 
questions relating to the construction, care and operation of gasoline and 
electric automobiles, including Road Troubles, Motor Troubles, Carbu- 
reter Troubles, ignition Troubles, Battery 
Troubles, Clutch Troubles, Starting 
Troubles. Pocket size, 4x6%. Over 200 
pages. With numerous tables, useful 
rules and formulas, wiring diagrams and 
over 100 illustrations, by 

L. ELLIOTT BROOKES 

Author of the " Construction of a Gasoline Motor." 




This work has been written especially 
for the practical information of automo- 
bile owners, operators and automobile 
mechanics. Questions will arise, which 
are answered or explained in technical 
books or trade journals, but such works 
are not always at hand, or the information 
given in them not directly applicable to the 
case in hand. 

In presenting this work to readers who may be interested in automo- 
biles, it has been the aim to treat the subject-matter therein in as simple 
and non-technical a manner as possible, and yet to give the principles, 
construction and operation of the different devices described, briefly and 
explicitly, and to illustrate them by showing constructions and methods 
used on modern types of American and European cars. 

The perusal of this work for a few minutes when troubles occur, will 
often not only save time, money and worry, but give greater confidence in 
the car, with regard to its going qualities on the road, when properly and 
intelligently cared for. 

In conclusion it may be stated that at the present time nearly all auto- 
mobile troubles or breakdowns may, in almost everycase.be traced to 
the lack of knowledge or carelessness of the owner or operator of the car. 
rather than to the car itself. 16mo. 320 pages, and over 100 illustrations. 

Popular Edition, Full Leather Limp. Price net $1.50 

Edition de Luxe, Full Red Morocco, Gold Edges. Price net.. 2.00 

Sent Postpaid to any Address in the World upon Receipt of Price 
FREDERICK J. DRAKE CSL COMPANY ® Publishers 
211-213 Ee^st Madison Street - - CHICAGO, ILL. 



The Practical Gas & 
Oil Engine hand-book 




i 
i 

its 







A MANUAL of useful in- 
■**- formation o n the care, 
maintenance and repair of Gas 
and Oil Engines. 

This work gives full and 
clear instructions on all points 
relating to the care, mainte- 
nance and repair of Stationary, 
Portable and Marine, Gas and 
Oil Engines, including How to 
Start, How to Stop, How to Ad- 
just, How to Repair, How to 
Test. 

Pocket size, 4x654. Over 
^ v. ;•;/••.;-";. .•S3S^ r \\lK|J>o^ll|J-. ".•*.••• 200 pages. With numerous 
*v^ •':'■"• '• ■■'•"■ '^(iitellv«^aC^^^^^'' - " ; ' : ' : '■"••"■' : rules and formulas and dia- 
grams, and over 50 illustrations 
by L. Elliott Brookes, au- 
thor of the "Construction of a 
Gasoline Motor," and the "Au- 
tomobile Hand-Book." 

This book has been written 
with the intention of furnishing 
practical information regarding 
gas, gasoline and kerosene engines, for the use of owners, operators and 
others who may be interested in their construction, operation and man- 
agement. 

In treating the various subjects it has been the endeavor to avoid all 
technical matter as far as possible, and to present the information given 
in a clear and practical manner. 

16mo. Popular Edition— Cloth. Price $1.00 

Edition de Luxe— Full Leather Limp. Price 1.50 

Sent Postpaid to any Address in the World upon Receipt of Price 

Frederick J. Drake £? Co. 

PUBLISHERS 

211-213 E. Madison Street * Chicago, 111. 



ALL TECHNICAL TERMS AVOIDED 

Practical Telepbone Hand Book and 
Guide to Telephonic ExchaDge^= 

HOW TO CONSTRUCT AND MAINTAIN TELEPHONE LINES 



By T. S. BALDWIN, M. A. Illustrated. 

Containing chapters on " The Use 
of the Telephone, Series and Bridg- 
ing phones, Line Construction, Ma- 
terials to be used, Locating and Cor- 
rection of Faults in Instruments 
and Lines." 

This is the best book ever pub- 
lished on Farm Telephones and has 
been the sensation of the past year 
in telephone circles. It is the only 
book ever issued which treats the 
subject exhaustively and compre- 
hensively. It is of inestimable value 
to promoters of rural party lines, 
because it contains all of the argu- 
ments that are necessary to show 
the advantages of rural party lines. 
It aiso tells how such lines should 
be constructed and cared for. 
The great growth jf the telephone industry during the past 
few years, and in response to the demand for a comprehensive 
book, giving a clear, terse idea of the different principles govern- 
ing the construction, installation, care and management of the 
various telephones and their appliances, the Practical Telephone 
Hand Book has been compiled. It is written in a most clear and 
careful style and aims to give a complete review of the subject 
of telephony. 

No expense has been spared in gathering valuable informa- 
tton, and it has been the aim of the author to make this treatise 
the most complete elementary book ever written on this subject 
for all persons interested in thi3 great achievement of modern 




The text is profusely illustrated by cuts of commercial ap- 
paratus and carefully prepared diagrams of circuits. No dia- 
gram is given without a full explanation. The apparatus and 
metbod3usedin making all the tests required in commercial 
telephone work, including the exchange, are fully treated. 
19, Mo- nioth. f ullv illustrated, price 



DYNAMO TENDING 




for 

ENGINEERS 

Or, ELECTRICITY 
FOR STEAM ENGINEER- 

By HENRY C. nORSTMANN and 
VICTOR H. TOUSLEY, 
Authors of "Modern Wiring Diagrams and 
Descriptions for Electrical Workers.'" 



This excellent treatise is written by 
engineers for engineers, and is a clear 
and comprehensive treatise on the prin- 
ciples, construction and operation of 
Dynamos, Motors, Lamps, Storage Bat- 
teries, Indicators and Measuring Instru- 
ments, as well as full explanations of the 
principles governing the generation 
of alternating currents and a descrip- 
tion of alternating current instruments and machinery. There are 
perhaps but few engineers who have not in the course of their labors 
come in contact with the electrical apparatus such as pertains to light 
and power distribution and generation. At the present rate of increase 
in the use of Electricity it is but a question of time when every steam 
installation will have in connecton with it an electrical generator, even 
in such buildings where light and power are supplied by some central 
station. It is essential that the man in charge of Engines, Boilers. 
Elevators, etc., be familiar with electrical matters, and it cannot well 
be other than an advantage to him and his employers. It is with a view 
to assisting engineers and others to obtain such knowledge as will enable 
them to intelligently manage such electrical apparatus as will ordinarily 
come under their control that this book has been written. The authors 
have had the co-operation of the best authorities, each in his chosen field, 
and the information given is just such as a steam engineer should know, 
To further this information, and to more carefully explain the text, 
nearly 100 illustrations are used, which, with perhaps a very few excep- 
tions, have been especially made for this book. There are many tables 
covering all sorts of electrical matters, so that immediate reference can 
be made without resorting to figuring. It covers the subject thoroughly, 
but so simply that any one can understand it fully. Any one making a 
pretense to electrical engineering needs this book. Nothing keeps a man 
down like the lack of training; nothing lifts him up as quickly or as 
surely as a thorough, practical knowledge of the work he has to do. This 
book "was written for the man without an opportunity. No matter what 
he is, or what work he has to do, it gives him just such information 
and training as are required to attain success. It teaches just what 
the steam engineer should know in his engine room about electricity. 
12mo, Cloth, 100 Illustrations. Size 5^x7%. PRICE NET A I M 
Sold by bookseller s generally, or sent, all charges paid, upon ty 1 1 U II 
receipt of price 

FREDERICK J. DRAKE Q COMPANY 

Publishers of Self- Educational Books for Mechanics 

21 1-2 13 East Madison Stree* CHICAGO, U.S.A. 



THE NEW AIR BRAKE BOOK invaluable to Trainmen, Engineers 

Firemen, Conductors, Electric Motormen and Mechanics. 

The Latest and Best 1904 Edition. 

MODERN AIR BRAKE PRACTICE 

ITS USE AND ABUSE 

With Questions and Answers for Loeo-motive Engineers and Electric 
Motormen. By FRANK H. BUKESMITH. 

THE necessity for a modern, practical air 
brake instruction book was never 
greater than now, owing to the fact 
that railroad extension is being so ag- 
gressively pushed in all parts of America, 
and particularly because of the fact that 
recent legislation of our American congress, 
compelling railroads to bring up their air 
brake equipment to at least 50 per cent of 
the number of cars in servicers naturally 
causing all railroads to demand a greater 
efficiency on the part of their employes in 
the operation and maintenance of the 
automatic air brake. 

While there have been many air brake 
books written, we feel safe in saying that 
never before has the subject been treated in 
the same lucid, understandable manner in 
which our author has treated it in this new 
book. 

Mr. Dukesmith treats the subject en- 
tirely different from all other air brake 
writers, inasmuch as he has divided the 
subject into three distinct parts, as follows: 
In section one, he explains and illustrates 
the various parts of the air brake equip- 
ment and their duties; in section two, he 
treats of the various defects and their remedies; in section three, he treats of 
the philosophy of airbrake handling, together with tables and rules for com- 
puting brake power, leverage, etc. 

Every device now in usein the Westinghouse Air Brake System is fully explained 
and particular treatment is given the subject of the high speed brake in its pres- 
ent stage of development. 

In the addition to the Westinghouse automatic air brake, there is also given 
a full and complete treatment of the straight air brake as is now used on electric 
railways, in order that motormen may be able to master the necessary knowledge 
demanded of them in handling air brakes. 

Following each section is a complete list of questions and answers covering 
a thorough air brake examination. 

"Modern Air Brake Practice, Its Use and Abuse"' contains over two hundred 
and fifty pages and is profusely illustrated with engravings of all parts of the 
air brake equipment, and, as these engravings have been furnished by the West- 
inghouse Air Brake Company of Pittsburg, Pa., absolute authenticity is 
assured. 

You may have read many air brake books, but whether you have or not, 
you cannot afford to be without the benefits contained in this volume if you have 
anything whatever to do with the operation or maintenance of air brakes. 

The book is fully indexed and cross indexed, so that any subject can be 
turned to immediately , as desired. 

If you are already posted, you can become better posted. If you really want 
to know all that is worth knowing about air brake practice send for this book. 

12MO. CLOTH. PRICE ONLY 

Sold by booksellers generally or sent postpaid to any address 
, upon receipt of price. 




$1.50 



FREDERICK 

Publishers of Self 
211-213 E. MADISON 




KE^ COMPANY 

Boo^g|fflfr\\Iechaiiics 

7 WHICAGO, U.S.A. 



SEP 6 1905 






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